All views and tables in the exposed schema and accessible by the active database role for a request are available for querying. They are exposed in one-level deep routes. For instance the full contents of a table people is returned at
GET /people HTTP/1.1There are no deeply/nested/routes. Each route provides OPTIONS, GET, HEAD, POST, PATCH, and DELETE verbs depending entirely on database permissions.
Note
Why not provide nested routes? Many APIs allow nesting to retrieve related information, such as /films/1/director. We offer a more flexible mechanism (inspired by GraphQL) to embed related information. It can handle one-to-many and many-to-many relationships. This is covered in the section about :ref:`resource_embedding`.
You can filter result rows by adding conditions on columns, each condition a query string parameter. For instance, to return people aged under 13 years old:
GET /people?age=lt.13 HTTP/1.1Multiple parameters can be logically conjoined by:
GET /people?age=gte.18&student=is.true HTTP/1.1Multiple parameters can be logically disjoined by:
GET /people?or=(age.gte.14,age.lte.18) HTTP/1.1Complex logic can also be applied:
GET /people?and=(grade.gte.90,student.is.true,or(age.gte.14,age.is.null)) HTTP/1.1These operators are available:
| Abbreviation | In PostgreSQL | Meaning |
|---|---|---|
| eq | = |
equals |
| gt | > |
greater than |
| gte | >= |
greater than or equal |
| lt | < |
less than |
| lte | <= |
less than or equal |
| neq | <> or != |
not equal |
| like | LIKE |
LIKE operator (use * in place of %) |
| ilike | ILIKE |
ILIKE operator (use * in place of %) |
| in | IN |
one of a list of values, e.g. ?a=in.(1,2,3)
– also supports commas in quoted strings like
?a=in.("hi,there","yes,you") |
| is | IS |
checking for exact equality (null,true,false) |
| fts | @@ |
:ref:`fts` using to_tsquery |
| plfts | @@ |
:ref:`fts` using plainto_tsquery |
| phfts | @@ |
:ref:`fts` using phraseto_tsquery |
| wfts | @@ |
:ref:`fts` using websearch_to_tsquery |
| cs | @> |
contains e.g. ?tags=cs.{example, new} |
| cd | <@ |
contained in e.g. ?values=cd.{1,2,3} |
| ov | && |
overlap (have points in common), e.g. ?period=ov.[2017-01-01,2017-06-30] –
also supports array types, use curly braces instead of square brackets e.g.
:code: ?arr=ov.{1,3} |
| sl | << |
strictly left of, e.g. ?range=sl.(1,10) |
| sr | >> |
strictly right of |
| nxr | &< |
does not extend to the right of, e.g. ?range=nxr.(1,10) |
| nxl | &> |
does not extend to the left of |
| adj | -|- |
is adjacent to, e.g. ?range=adj.(1,10) |
| not | NOT |
negates another operator, see below |
To negate any operator, prefix it with not like ?a=not.eq.2 or ?not.and=(a.gte.0,a.lte.100) .
For more complicated filters you will have to create a new view in the database, or use a stored procedure. For instance, here's a view to show "today's stories" including possibly older pinned stories:
CREATE VIEW fresh_stories AS
SELECT *
FROM stories
WHERE pinned = true
OR published > now() - interval '1 day'
ORDER BY pinned DESC, published DESC;
The view will provide a new endpoint:
GET /fresh_stories HTTP/1.1The fts filter mentioned above has a number of options to support flexible textual queries, namely the choice of plain vs phrase search and the language used for stemming. Suppose that tsearch is a table with column my_tsv, of type tsvector. The following examples illustrate the possibilities.
GET /tsearch?my_tsv=fts(french).amusant HTTP/1.1GET /tsearch?my_tsv=plfts.The%20Fat%20Cats HTTP/1.1GET /tsearch?my_tsv=not.phfts(english).The%20Fat%20Cats HTTP/1.1GET /tsearch?my_tsv=not.wfts(french).amusant HTTP/1.1Using phrase search mode requires PostgreSQL of version at least 9.6 and will raise an error in earlier versions of the database.
Using websearch_to_tsquery requires PostgreSQL of version at least 11.0 and will raise an error in earlier versions of the database.
When certain columns are wide (such as those holding binary data), it is more efficient for the server to withhold them in a response. The client can specify which columns are required using the select parameter.
GET /people?select=first_name,age HTTP/1.1
[
{"first_name": "John", "age": 30},
{"first_name": "Jane", "age": 20}
]The default is *, meaning all columns. This value will become more important below in :ref:`resource_embedding`.
You can rename the columns by prefixing them with an alias followed by the colon : operator.
GET /people?select=fullName:full_name,birthDate:birth_date HTTP/1.1
[
{"fullName": "John Doe", "birthDate": "04/25/1988"},
{"fullName": "Jane Doe", "birthDate": "01/12/1998"}
]Casting the columns is possible by suffixing them with the double colon :: plus the desired type.
GET /people?select=full_name,salary::text HTTP/1.1
[
{"full_name": "John Doe", "salary": "90000.00"},
{"full_name": "Jane Doe", "salary": "120000.00"}
]You can specify a path for a json or jsonb column using the arrow operators(-> or ->>) as per the PostgreSQL docs.
GET /people?select=id,json_data->>blood_type,json_data->phones HTTP/1.1
[
{ "id": 1, "blood_type": "A-", "phones": [{"country_code": "61", "number": "917-929-5745"}] },
{ "id": 2, "blood_type": "O+", "phones": [{"country_code": "43", "number": "512-446-4988"}, {"country_code": "43", "number": "213-891-5979"}] }
]GET /people?select=id,json_data->phones->0->>number HTTP/1.1
[
{ "id": 1, "number": "917-929-5745"},
{ "id": 2, "number": "512-446-4988"}
]This also works with filters:
GET /people?select=id,json_data->blood_type&json_data->>blood_type=eq.A- HTTP/1.1
[
{ "id": 1, "blood_type": "A-" },
{ "id": 3, "blood_type": "A-" },
{ "id": 7, "blood_type": "A-" }
]Note that ->> is used to compare blood_type as text. To compare with an integer value use ->:
GET /people?select=id,json_data->age&json_data->age=gt.20 HTTP/1.1
[
{ "id": 11, "age": 25 },
{ "id": 12, "age": 30 },
{ "id": 15, "age": 35 }
]Filters may be applied to computed columns(a.k.a. virtual columns) as well as actual table/view columns, even though the computed columns will not appear in the output. For example, to search first and last names at once we can create a computed column that will not appear in the output but can be used in a filter:
CREATE TABLE people (
fname text,
lname text
);
CREATE FUNCTION full_name(people) RETURNS text AS $$
SELECT $1.fname || ' ' || $1.lname;
$$ LANGUAGE SQL;
-- (optional) add an index to speed up anticipated query
CREATE INDEX people_full_name_idx ON people
USING GIN (to_tsvector('english', full_name(people)));
A full-text search on the computed column:
GET /people?full_name=fts.Beckett HTTP/1.1As mentioned, computed columns do not appear in the output by default. However you can include them by listing them in the vertical filtering select parameter:
GET /people?select=*,full_name HTTP/1.1Important
Computed columns must be created under the :ref:`exposed schema <db-schema>` to be used in this way.
PostgREST supports unicode in schemas, tables, columns and values. To access a table with unicode name, use percent encoding.
To request this:
GET /موارد HTTP/1.1Do this:
GET /%D9%85%D9%88%D8%A7%D8%B1%D8%AF HTTP/1.1You can request table/columns with spaces in them by percent encoding the spaces with %20:
GET /Order%20Items?Unit%20Price=lt.200 HTTP/1.1If filters include PostgREST reserved characters(,, ., :, ()) you'll have to surround them in percent encoded double quotes %22 for correct processing.
Here Hebdon,John and Williams,Mary are values.
GET /employees?name=in.(%22Hebdon,John%22,%22Williams,Mary%22) HTTP/1.1Here information.cpe is a column name.
GET /vulnerabilities?%22information.cpe%22=like.*MS* HTTP/1.1Note
Some HTTP libraries might encode URLs automatically(e.g. axios). In these cases you should use double quotes
"" directly instead of %22.
The reserved word order reorders the response rows. It uses a comma-separated list of columns and directions:
GET /people?order=age.desc,height.asc HTTP/1.1If no direction is specified it defaults to ascending order:
GET /people?order=age HTTP/1.1If you care where nulls are sorted, add nullsfirst or nullslast:
GET /people?order=age.nullsfirst HTTP/1.1GET /people?order=age.desc.nullslast HTTP/1.1You can also use :ref:`computed_cols` to order the results, even though the computed columns will not appear in the output.
PostgREST uses HTTP range headers to describe the size of results. Every response contains the current range and, if requested, the total number of results:
HTTP/1.1 200 OK
Range-Unit: items
Content-Range: 0-14/*Here items zero through fourteen are returned. This information is available in every response and can help you render pagination controls on the client. This is an RFC7233-compliant solution that keeps the response JSON cleaner.
There are two ways to apply a limit and offset rows: through request headers or query parameters. When using headers you specify the range of rows desired. This request gets the first twenty people.
GET /people HTTP/1.1
Range-Unit: items
Range: 0-19Note that the server may respond with fewer if unable to meet your request:
HTTP/1.1 200 OK
Range-Unit: items
Content-Range: 0-17/*You may also request open-ended ranges for an offset with no limit, e.g. Range: 10-.
The other way to request a limit or offset is with query parameters. For example
GET /people?limit=15&offset=30 HTTP/1.1This method is also useful for embedded resources, which we will cover in another section. The server always responds with range headers even if you use query parameters to limit the query.
In order to obtain the total size of the table or view (such as when rendering the last page link in a pagination control), specify Prefer: count=exact as a request header:
HEAD /bigtable HTTP/1.1
Range-Unit: items
Range: 0-24
Prefer: count=exactNote that the larger the table the slower this query runs in the database. The server will respond with the selected range and total
HTTP/1.1 206 Partial Content
Range-Unit: items
Content-Range: 0-24/3573458To avoid the shortcomings of :ref:`exact count <exact_count>`, PostgREST can leverage PostgreSQL statistics and get a fairly accurate and fast count.
To do this, specify the Prefer: count=planned header.
HEAD /bigtable?limit=25 HTTP/1.1
Prefer: count=plannedHTTP/1.1 206 Partial Content
Content-Range: 0-24/3572000Note that the accuracy of this count depends on how up-to-date are the PostgreSQL statistics tables.
For example in this case, to increase the accuracy of the count you can do ANALYZE bigtable.
See ANALYZE for more details.
When you are interested in the count, the relative error is important. If you have a :ref:`planned count <planned_count>` of 1000000 and the exact count is 1001000, the error is small enough to be ignored. But with a planned count of 7, an exact count of 28 would be a huge misprediction.
In general, when having smaller row-counts, the estimated count should be as close to the exact count as possible.
To help with these cases, PostgREST can get the exact count up until a threshold and get the planned count when
that threshold is surpassed. To use this behavior, you can specify the Prefer: count=estimated header. The threshold is
defined by :ref:`max-rows`.
Here's an example. Suppose we set max-rows=1000 and smalltable has 321 rows, then we'll get the exact count:
HEAD /smalltable?limit=25 HTTP/1.1
Prefer: count=estimatedHTTP/1.1 206 Partial Content
Content-Range: 0-24/321If we make a similar request on bigtable, which has 3573458 rows, we would get the planned count:
HEAD /bigtable?limit=25 HTTP/1.1
Prefer: count=estimatedHTTP/1.1 206 Partial Content
Content-Range: 0-24/3572000PostgREST uses proper HTTP content negotiation (RFC7231) to deliver the desired representation of a resource. That is to say the same API endpoint can respond in different formats like JSON or CSV depending on the client request.
Use the Accept request header to specify the acceptable format (or formats) for the response:
GET /people HTTP/1.1
Accept: application/jsonThe current possibilities are:
*/*text/csvapplication/jsonapplication/openapi+jsonapplication/octet-stream
The server will default to JSON for API endpoints and OpenAPI on the root.
By default PostgREST returns all JSON results in an array, even when there is only one item. For example, requesting /items?id=eq.1 returns
[
{ "id": 1 }
]This can be inconvenient for client code. To return the first result as an object unenclosed by an array, specify vnd.pgrst.object as part of the Accept header
GET /items?id=eq.1 HTTP/1.1
Accept: application/vnd.pgrst.object+jsonThis returns
{ "id": 1 }When a singular response is requested but no entries are found, the server responds with an error message and 406 Not Acceptable status code rather than the usual empty array and 200 status:
{
"message": "JSON object requested, multiple (or no) rows returned",
"details": "Results contain 0 rows, application/vnd.pgrst.object+json requires 1 row"
}Note
Many APIs distinguish plural and singular resources using a special nested URL convention e.g. /stories vs /stories/1. Why do we use /stories?id=eq.1? The answer is because a singular resource is (for us) a row determined by a primary key, and primary keys can be compound (meaning defined across more than one column). The more familiar nested urls consider only a degenerate case of simple and overwhelmingly numeric primary keys. These so-called artificial keys are often introduced automatically by Object Relational Mapping libraries.
Admittedly PostgREST could detect when there is an equality condition holding on all columns constituting the primary key and automatically convert to singular. However this could lead to a surprising change of format that breaks unwary client code just by filtering on an extra column. Instead we allow manually specifying singular vs plural to decouple that choice from the URL format.
In addition to providing RESTful routes for each table and view, PostgREST allows related resources to be included together in a single API call. This reduces the need for multiple API requests. The server uses foreign keys to determine which tables and views can be returned together. For example, consider a database of films and their awards:
Important
PostgREST needs FOREIGN KEY constraints to be able to do Resource Embedding.
As seen above in :ref:`v_filter` we can request the titles of all films like this:
GET /films?select=title HTTP/1.1This might return something like
[
{ "title": "Workers Leaving The Lumière Factory In Lyon" },
{ "title": "The Dickson Experimental Sound Film" },
{ "title": "The Haunted Castle" }
]However because a foreign key constraint exists between Films and Directors, we can request this information be included:
GET /films?select=title,directors(id,last_name) HTTP/1.1Which would return
[
{ "title": "Workers Leaving The Lumière Factory In Lyon",
"directors": {
"id": 2,
"last_name": "Lumière"
}
},
{ "title": "The Dickson Experimental Sound Film",
"directors": {
"id": 1,
"last_name": "Dickson"
}
},
{ "title": "The Haunted Castle",
"directors": {
"id": 3,
"last_name": "Méliès"
}
}
]In this example, since the relationship is a forward relationship, there is only one director associated with a film. As the table name is plural it might be preferable for it to be singular instead. An table name alias can accomplish this:
GET /films?select=title,director:directors(id,last_name) HTTP/1.1Important
Whenever FOREIGN KEY constraints change in the database schema you must refresh PostgREST's schema cache for Resource Embedding to work properly. See the section :ref:`schema_reloading`.
PostgREST can also detect relationships going through join tables. Thus you can request the Actors for Films (which in this case finds the information through Roles).
GET /actors?select=films(title,year) HTTP/1.1Embedded resources can be shaped similarly to their top-level counterparts. To do so, prefix the query parameters with the name of the embedded resource. For instance, to order the actors in each film:
GET /films?select=*,actors(*)&actors.order=last_name,first_name HTTP/1.1This sorts the list of actors in each film but does not change the order of the films themselves. To filter the roles returned with each film:
GET /films?select=*,roles(*)&roles.character=in.(Chico,Harpo,Groucho) HTTP/1.1Once again, this restricts the roles included to certain characters but does not filter the films in any way. Films without any of those characters would be included along with empty character lists.
An or filter can be used for a similar operation:
GET /films?select=*,roles(*)&roles.or=(character.eq.Gummo,character.eq.Zeppo) HTTP/1.1Limit and offset operations are possible:
GET /films?select=*,actors(*)&actors.limit=10&actors.offset=2 HTTP/1.1Embedded resources can be aliased and filters can be applied on these aliases:
GET /films?select=*,90_comps:competitions(name),91_comps:competitions(name)&90_comps.year=eq.1990&91_comps.year=eq.1991 HTTP/1.1Embedding a view is possible if the view contains columns that have foreign keys defined in their source tables.
As an example, let's create a view called nominations_view based on the nominations table.
CREATE VIEW nominations_view AS
SELECT
rank
, competition_id
, film_id
FROM
nominations;
Since it contains competition_id and film_id — and each one has a foreign key defined in its source table — we can embed competitions and films:
GET /nominations_view?select=rank,competitions(name,year),films(title)&rank=eq.5 HTTP/1.1It's also possible to embed Materialized Views.
Warning
It's not guaranteed that all kinds of views will be embeddable. In particular, views that contain UNIONs will not be made embeddable.
Why? PostgREST detects source table foreign keys in the view by querying and parsing pg_rewrite. This may fail depending on the complexity of the view.
Report an issue if your view is not made embeddable so we can keep continue improving foreign key detection.
In the future we'll include a way to manually specify views source foreign keys to address this limitation.
Important
If view definitions change you must refresh PostgREST's schema cache for this to work properly. See the section :ref:`schema_reloading`.
Views can also depend on other views, which in turn depend on the actual source table. For PostgREST to pick up those chains recursively to any depth, all the views must be in the search path, so either in the exposed schema (:ref:`db-schema`) or in one of the schemas set in :ref:`db-extra-search-path`. This does not apply to the source table, which could be in a private schema as well. See :ref:`schema_isolation` for more details.
If you have a :ref:`Stored Procedure <s_procs>` that returns a table type, you can embed its related resources.
Here's a sample function (notice the RETURNS SETOF films).
CREATE FUNCTION getallfilms() RETURNS SETOF films AS $$
SELECT * FROM films;
$$ LANGUAGE SQL IMMUTABLE;A request with directors embedded:
GET /rpc/getallfilms?select=title,directors(id,last_name)&title=like.*Workers* HTTP/1.1[
{ "title": "Workers Leaving The Lumière Factory In Lyon",
"directors": {
"id": 2,
"last_name": "Lumière"
}
}
]You can embed related resources after doing :ref:`insert_update` or :ref:`delete`.
Say you want to insert a film and then get some of its attributes plus embed its director.
POST /films?select=title,year,director:directors(first_name,last_name) HTTP/1.1
Prefer: return=representation
{
"id": 100,
"director_id": 40,
"title": "127 hours",
"year": 2010,
"rating": 7.6,
"language": "english"
}Response:
{
"title": "127 hours",
"year": 2010,
"director": {
"first_name": "Danny",
"last_name": "Boyle"
}
}For doing resource embedding, PostgREST infers the relationship between two tables based on a foreign key between them. However, in cases where there's more than one foreign key between two tables, it's not possible to infer the relationship unambiguously by just specifying the tables names.
For example, suppose you have the following orders and addresses tables:
And you try to embed orders with addresses (this is the target):
GET /orders?select=*,addresses(*) HTTP/1.1Since the orders table has two foreign keys to the addresses table — an order has a billing address and a shipping address —
the request is ambiguous and PostgREST will respond with an error:
HTTP/1.1 300 Multiple ChoicesIf this happens, you need to disambiguate the request by adding precision to the target. Instead of the table name, you can specify the foreign key constraint name or the column name that is part of the foreign key.
Let's try first with the foreign key constraint name. To make it clearer we can name it:
ALTER TABLE orders
ADD CONSTRAINT billing_address foreign key (billing_address_id) references addresses(id),
ADD CONSTRAINT shipping_address foreign key (shipping_address_id) references addresses(id);
-- Or if the constraints names were already generated by PostgreSQL we can rename them
-- ALTER TABLE orders
-- RENAME CONSTRAINT orders_billing_address_id_fkey TO billing_address,
-- RENAME CONSTRAINT orders_shipping_address_id_fkey TO shipping_address;
Now we can unambiguously embed the billing address by specifying the billing_address foreign key constraint as the target.
GET /orders?select=name,billing_address(name) HTTP/1.1
[
{
"name": "Personal Water Filter",
"billing_address": {
"name": "32 Glenlake Dr.Dearborn, MI 48124"
}
}
]Alternatively, you can specify the column name of the foreign key constraint as the target. This can be aliased to make the result more clear.
GET /orders?select=name,billing_address:billing_address_id(name) HTTP/1.1
[
{
"name": "Personal Water Filter",
"billing_address": {
"name": "32 Glenlake Dr.Dearborn, MI 48124"
}
}
]If specifying the target is not enough for unambiguous embedding, you can add a hint. For example, let's assume we create
two views of addresses: central_addresses and eastern_addresses.
Since PostgREST supports :ref:`embedding_views` by detecting source foreign keys in the views, embedding with the foreign key as the target will not be enough for an unambiguous embed:
GET /orders?select=*,billing_address(*) HTTP/1.1
HTTP/1.1 300 Multiple ChoicesFor solving this case, in addition to the target, we can add a hint.
Here we specify central_addresses as the target and the billing_address foreign key as the hint:
GET /orders?select=*,central_addresses!billing_address(*) HTTP/1.1
HTTP/1.1 200 OK
[ ... ]Similarly to the target, the hint can be a table name, foreign key constraint name or column name.
All tables and auto-updatable views can be modified through the API, subject to permissions of the requester's database role.
To create a row in a database table post a JSON object whose keys are the names of the columns you would like to create. Missing properties will be set to default values when applicable.
POST /table_name HTTP/1.1
{ "col1": "value1", "col2": "value2" }If the table has a primary key, the response will include a Location header describing where to find the new object. If the table is write-only then constructing the Location header will cause a permissions error. To successfully insert an item to a write-only table you will need to suppress the Location response header by including the request header Prefer: return=minimal.
On the other end of the spectrum you can get the full created object back in the response to your request by including the header Prefer: return=representation. That way you won't have to make another HTTP call to discover properties that may have been filled in on the server side. You can also apply the standard :ref:`v_filter` to these results.
URL encoded payloads can be posted with Content-Type: application/x-www-form-urlencoded.
POST /people HTTP/1.1
Content-Type: application/x-www-form-urlencoded
name=John+Doe&age=50&weight=80Note
When inserting a row you must post a JSON object, not quoted JSON.
Yes
{ "a": 1, "b": 2 }
No
"{ \"a\": 1, \"b\": 2 }"
Some JavaScript libraries will post the data incorrectly if you're not careful. For best results try one of the :ref:`clientside_libraries` built for PostgREST.
To update a row or rows in a table, use the PATCH verb. Use :ref:`h_filter` to specify which record(s) to update. Here is an example query setting the category column to child for all people below a certain age.
PATCH /people?age=lt.13 HTTP/1.1
{ "category": "child" }Updates also support Prefer: return=representation plus :ref:`v_filter`.
Warning
Beware of accidentally updating every row in a table. To learn to prevent that see :ref:`block_fulltable`.
Bulk insert works exactly like single row insert except that you provide either a JSON array of objects having uniform keys, or lines in CSV format. This not only minimizes the HTTP requests required but uses a single INSERT statement on the back-end for efficiency. Note that using CSV requires less parsing on the server and is much faster.
To bulk insert CSV simply post to a table route with Content-Type: text/csv and include the names of the columns as the first row. For instance
POST /people HTTP/1.1
Content-Type: text/csv
name,age,height
J Doe,62,70
Jonas,10,55An empty field (,,) is coerced to an empty string and the reserved word NULL is mapped to the SQL null value. Note that there should be no spaces between the column names and commas.
To bulk insert JSON post an array of objects having all-matching keys
POST /people HTTP/1.1
Content-Type: application/json
[
{ "name": "J Doe", "age": 62, "height": 70 },
{ "name": "Janus", "age": 10, "height": 55 }
]By using the columns query parameter it's possible to specify the payload keys that will be inserted/updated
and ignore the rest of the payload.
POST /datasets?columns=source,publication_date,figure HTTP/1.1
Content-Type: application/json
{
"source": "Natural Disaster Prevention and Control",
"publication_date": "2015-09-11",
"figure": 1100,
"location": "...",
"comment": "...",
"extra": "...",
"stuff": "..."
}In this case, only source, publication_date and figure will be inserted. The rest of the JSON keys will be ignored.
Using this also has the side-effect of being more efficient for :ref:`bulk_insert` since PostgREST will not process the JSON and it'll send it directly to PostgreSQL.
You can make an UPSERT with POST and the Prefer: resolution=merge-duplicates header:
POST /employees HTTP/1.1
Prefer: resolution=merge-duplicates
[
{ "id": 1, "name": "Old employee 1", "salary": 30000 },
{ "id": 2, "name": "Old employee 2", "salary": 42000 },
{ "id": 3, "name": "New employee 3", "salary": 50000 }
]By default, UPSERT operates based on the primary key columns, you must specify all of them. You can also choose to ignore the duplicates with Prefer: resolution=ignore-duplicates. This works best when the primary key is natural, but it's also possible to use it if the primary key is surrogate (example: "id serial primary key"). For more details read this issue.
Important
After creating a table or changing its primary key, you must refresh PostgREST schema cache for UPSERT to work properly. To learn how to refresh the cache see :ref:`schema_reloading`.
By specifying the on_conflict query parameter, you can make UPSERT work on a column(s) that has a UNIQUE constraint.
POST /employees?on_conflict=name HTTP/1.1
Prefer: resolution=merge-duplicates
[
{ "name": "Old employee 1", "salary": 40000 },
{ "name": "Old employee 2", "salary": 52000 },
{ "name": "New employee 3", "salary": 60000 }
]A single row UPSERT can be done by using PUT and filtering the primary key columns with eq:
PUT /employees?id=eq.4 HTTP/1.1
{ "id": 4, "name": "Sara B.", "salary": 60000 }All the columns must be specified in the request body, including the primary key columns.
Note
Upsert features are only available starting from PostgreSQL 9.5 since it uses the ON CONFLICT clause.
To delete rows in a table, use the DELETE verb plus :ref:`h_filter`. For instance deleting inactive users:
DELETE /user?active=is.false HTTP/1.1Deletions also support Prefer: return=representation plus :ref:`v_filter`.
DELETE /user?id=eq.1 HTTP/1.1
Prefer: return=representation
{"id": 1, "email": "[email protected]"}Warning
Beware of accidentally deleting all rows in a table. To learn to prevent that see :ref:`block_fulltable`.
The PostgREST URL grammar limits the kinds of queries clients can perform. It prevents arbitrary, potentially poorly constructed and slow client queries. It's good for quality of service, but means database administrators must create custom views and stored procedures to provide richer endpoints. The most common causes for custom endpoints are
- Table unions
- More complicated joins than those provided by Resource Embedding
- Geo-spatial queries that require an argument, like "points near (lat,lon)"
Every stored procedure in the API-exposed database schema is accessible under the /rpc prefix. The API endpoint supports POST (and in some cases GET) to execute the function.
POST /rpc/function_name HTTP/1.1Such functions can perform any operations allowed by PostgreSQL (read data, modify data, and even DDL operations).
To supply arguments in an API call, include a JSON object in the request payload and each key/value of the object will become an argument.
For instance, assume we have created this function in the database.
CREATE FUNCTION add_them(a integer, b integer)
RETURNS integer AS $$
SELECT a + b;
$$ LANGUAGE SQL IMMUTABLE;Important
Whenever you create or change a function you must refresh PostgREST's schema cache. See the section :ref:`schema_reloading`.
If the schema cache is not refreshed, PostgREST will assume text as the default type for function arguments. This could
lead to getting error responses like:
{
"hint":"No function matches the given name and argument types. You might need to add explicit type casts.",
"details":null,
"code":"42883",
"message":"function test.add_them(a => text, b => text) does not exist"
}The client can call it by posting an object like
POST /rpc/add_them HTTP/1.1
{ "a": 1, "b": 2 }
3Procedures must be declared with named parameters. Procedures declared like
CREATE FUNCTION non_named_args(integer, text, integer) ...cannot be called with PostgREST, since we use named notation internally.
Note that PostgreSQL converts identifier names to lowercase unless you quote them like:
CREATE FUNCTION "someFunc"("someParam" text) ...
PostgreSQL has four procedural languages that are part of the core distribution: PL/pgSQL, PL/Tcl, PL/Perl, and PL/Python. There are many other procedural languages distributed as additional extensions. Also, plain SQL can be used to write functions (as shown in the example above).
Note
Why the /rpc prefix? One reason is to avoid name collisions between views and procedures. It also helps emphasize to API consumers that these functions are not normal restful things. The functions can have arbitrary and surprising behavior, not the standard "post creates a resource" thing that users expect from the other routes.
PostgREST executes POST requests in a read/write transaction except for functions marked as IMMUTABLE or STABLE. Those must not modify the database and are executed in a read-only transaction compatible for read-replicas.
Procedures that do not modify the database can be called with the HTTP GET verb as well, if desired. PostgREST executes all GET requests in a read-only transaction. Modifying the database inside read-only transactions is not possible and calling volatile functions with GET will fail.
Note
The volatility marker is a promise about the behavior of the function. PostgreSQL will let you mark a function that modifies the database as IMMUTABLE or STABLE without failure. However, because of the read-only transaction this would still fail with PostgREST.
Because add_them is IMMUTABLE, we can alternately call the function with a GET request:
GET /rpc/add_them?a=1&b=2 HTTP/1.1The function parameter names match the JSON object keys in the POST case, for the GET case they match the query parameters ?a=1&b=2.
You can also call a function that takes a single parameter of type JSON by sending the header Prefer: params=single-object with your request. That way the JSON request body will be used as the single argument.
CREATE FUNCTION mult_them(param json) RETURNS int AS $$
SELECT (param->>'x')::int * (param->>'y')::int
$$ LANGUAGE SQL;POST /rpc/mult_them HTTP/1.1
Prefer: params=single-object
{ "x": 4, "y": 2 }
8You can call a function that takes an array parameter:
create function plus_one(arr int[]) returns int[] as $$
SELECT array_agg(n + 1) FROM unnest($1) AS n;
$$ language sql;
POST /rpc/plus_one HTTP/1.1
Content-Type: application/json
{"arr": [1,2,3,4]}[2,3,4,5]For calling the function with GET, you can pass the array as an array literal,
as in {1,2,3,4}. Note that the curly brackets have to be urlencoded({ is %7B and } is %7D).
GET /rpc/plus_one?arr=%7B1,2,3,4%7D' HTTP/1.1Note
For versions prior to PostgreSQL 10, to pass a PostgreSQL native array on a POST payload, you need to quote it and use an array literal:
POST /rpc/plus_one HTTP/1.1
{ "arr": "{1,2,3,4}" }In these versions we recommend using function parameters of type JSON to accept arrays from the client.
You can call a variadic function by passing a JSON array in a POST request:
create function plus_one(variadic v int[]) returns int[] as $$
SELECT array_agg(n + 1) FROM unnest($1) AS n;
$$ language sql;
POST /rpc/plus_one HTTP/1.1
Content-Type: application/json
{"v": [1,2,3,4]}[2,3,4,5]In a GET request, you can repeat the same parameter name:
GET /rpc/plus_one?v=1&v=2&v=3&v=4 HTTP/1.1Repeating also works in POST requests with Content-Type: application/x-www-form-urlencoded:
POST /rpc/plus_one HTTP/1.1
Content-Type: application/x-www-form-urlencoded
v=1&v=2&v=3&v=4PostgREST will detect if the function is scalar or table-valued and will shape the response format accordingly:
GET /rpc/add_them?a=1&b=2 HTTP/1.1
3GET /rpc/best_films_2017 HTTP/1.1
[
{ "title": "Okja", "rating": 7.4},
{ "title": "Call me by your name", "rating": 8},
{ "title": "Blade Runner 2049", "rating": 8.1}
]It's possible to call a function in a bulk way, analogously to :ref:`bulk_insert`. To do this, you need to add the
Prefer: params=multiple-objects header to your request.
POST /rpc/add_them HTTP/1.1
Content-Type: text/csv
Prefer: params=multiple-objects
a,b
1,2
3,4[ 3, 7 ]If you have large payloads to process, it's preferable you instead use a function with an :ref:`array parameter <s_procs_array>` or JSON parameter, as this will be more efficient.
It's also possible to :ref:`Specify Columns <specify_columns>` on functions calls.
A function that returns a table type response can be shaped using the same filters as the ones used for tables and views:
CREATE FUNCTION best_films_2017() RETURNS SETOF films ..
GET /rpc/best_films_2017?select=title,director:directors(*) HTTP/1.1GET /rpc/best_films_2017?rating=gt.8&order=title.desc HTTP/1.1You can call overloaded functions with different number of arguments.
CREATE FUNCTION rental_duration(customer_id integer) ..
CREATE FUNCTION rental_duration(customer_id integer, from_date date) ..
GET /rpc/rental_duration?customer_id=232 HTTP/1.1GET /rpc/rental_duration?customer_id=232&from_date=2018-07-01 HTTP/1.1If you want to return raw binary data from a bytea column, you must specify application/octet-stream as part of the Accept header
and select a single column ?select=bin_data.
GET /items?select=bin_data&id=eq.1 HTTP/1.1
Accept: application/octet-streamYou can also request binary output when calling Stored Procedures and since they can return a scalar value you are not forced to use select
for this case.
CREATE FUNCTION closest_point(..) RETURNS bytea ..
POST /rpc/closest_point HTTP/1.1
Accept: application/octet-streamIf the stored procedure returns non-scalar values, you need to do a select in the same way as for GET binary output.
CREATE FUNCTION overlapping_regions(..) RETURNS SETOF TABLE(geom_twkb bytea, ..) ..POST /rpc/overlapping_regions?select=geom_twkb HTTP/1.1
Accept: application/octet-streamNote
If more than one row would be returned the binary results will be concatenated with no delimiter.
You can get raw output from a text column by using Accept: text/plain.
GET /workers?select=custom_psv_format HTTP/1.1
Accept: text/plain
09310817|JOHN|DOE|15/04/88|
42152780|FRED|BLOGGS|20/02/85|
43006541|OTTO|NORMALVERBRAUCHER|01/07/90|
02452492|ERIKA|MUSTERMANN|11/01/80|This follows the same rules as :ref:`binary_output`.
Every API hosted by PostgREST automatically serves a full OpenAPI description on the root path. This provides a list of all endpoints(tables, foreign tables, views, functions), along with supported HTTP verbs and example payloads. For extra customization, the OpenAPI output contains a "description" field for every SQL comment on any database object. For instance,
COMMENT ON SCHEMA mammals IS
'A warm-blooded vertebrate animal of a class that is distinguished by the secretion of milk by females for the nourishment of the young';
COMMENT ON TABLE monotremes IS
'Freakish mammals lay the best eggs for breakfast';
COMMENT ON COLUMN monotremes.has_venomous_claw IS
'Sometimes breakfast is not worth it';These unsavory comments will appear in the generated JSON as the fields, info.description, definitions.monotremes.description and definitions.monotremes.properties.has_venomous_claw.description.
Also if you wish to generate a summary field you can do it by having a multiple line comment, the summary will be the first line and the description the lines that follow it:
COMMENT ON TABLE entities IS
$$Entities summary
Entities description that
spans
multiple lines$$;You can use a tool like Swagger UI to create beautiful documentation from the description and to host an interactive web-based dashboard. The dashboard allows developers to make requests against a live PostgREST server, and provides guidance with request headers and example request bodies.
Important
The OpenAPI information can go out of date as the schema changes under a running server. To learn how to refresh the cache see :ref:`schema_reloading`.
You can switch schemas at runtime with the Accept-Profile and Content-Profile headers. You can only switch to a schema that is included in :ref:`db-schema`.
For GET or HEAD, the schema to be used can be selected through the Accept-Profile header:
GET /items HTTP/1.1
Accept-Profile: tenant2For POST, PATCH, PUT and DELETE, you can use the Content-Profile header for selecting the schema:
POST /items HTTP/1.1
Content-Profile: tenant2
{...}You can also select the schema for :ref:`s_procs` and :ref:`open-api`.
Note
These headers are based on the nascent "Content Negotiation by Profile" spec: https://www.w3.org/TR/dx-prof-conneg
You can access request headers, cookies and JWT claims by reading GUC variables set by PostgREST per request. They are named request.header.XYZ, request.cookie.XYZ and request.jwt.claim.XYZ.
-- To read the value of the Origin request header:
SELECT current_setting('request.header.origin', true);
-- To read the value of sessionId in a cookie:
SELECT current_setting('request.cookie.sessionId', true);
-- To read the value of the email claim in a jwt:
SELECT current_setting('request.jwt.claim.email', true);
Note
request.jwt.claim.role defaults to the value of :ref:`db-anon-role`.
You can also access the request path and method with request.path and request.method.
-- You can get the path of the request with
SELECT current_setting('request.path', true);
-- You can get the method of the request with
SELECT current_setting('request.method', true);
PostgREST reads the response.headers SQL variable to add extra headers to the HTTP response. Stored procedures can modify this variable. For instance, this statement would add caching headers to the response:
-- tell client to cache response for two days
SELECT set_config('response.headers',
'[{"Cache-Control": "public"}, {"Cache-Control": "max-age=259200"}]', true);Notice that the variable should be set to an array of single-key objects rather than a single multiple-key object. This is because headers such as Cache-Control or Set-Cookie need to be repeated when setting multiple values and an object would not allow the repeated key.
Note
PostgREST provided headers such as Content-Type, Location, etc. can be overriden this way.
By using a :ref:`pre-request` function, you can add headers to GET/POST/PATCH/PUT/DELETE responses. As an example, let's add some cache headers for all requests that come from an Internet Explorer(6 or 7) browser.
create or replace function custom_headers() returns void as $$
declare
user_agent text := current_setting('request.header.user-agent', true);
begin
if user_agent similar to '%MSIE (6.0|7.0)%' then
perform set_config('response.headers',
'[{"Cache-Control": "no-cache, no-store, must-revalidate"}]', false);
end if;
end; $$ language plpgsql;
-- set this function on postgrest.conf
-- pre-request = custom_headers
Now when you make a GET request to a table or view, you'll get the cache headers.
GET /people HTTP/1.1
User-Agent: Mozilla/4.01 (compatible; MSIE 6.0; Windows NT 5.1)
HTTP/1.1 200 OK
Content-Type: application/json; charset=utf-8
Cache-Control: no-cache, no-store, must-revalidate
...You can set the response.status GUC to override the default status code PostgREST provides. For instance, the following function would replace the default 200 status code.
create or replace function teapot() returns json as $$
begin
perform set_config('response.status', '418', true);
return json_build_object('message', 'The requested entity body is short and stout.',
'hint', 'Tip it over and pour it out.');
end;
$$ language plpgsql;
GET /rpc/teapot HTTP/1.1HTTP/1.1 418 I'm a teapot
{"message" : "The requested entity body is short and stout.",
"hint" : "Tip it over and pour it out."}If the status code is standard, PostgREST will complete the status message(I'm a teapot in this example).
Stored procedures can return non-200 HTTP status codes by raising SQL exceptions. For instance, here's a saucy function that always responds with an error:
CREATE OR REPLACE FUNCTION just_fail() RETURNS void
LANGUAGE plpgsql
AS $$
BEGIN
RAISE EXCEPTION 'I refuse!'
USING DETAIL = 'Pretty simple',
HINT = 'There is nothing you can do.';
END
$$;
Calling the function returns HTTP 400 with the body
{
"message":"I refuse!",
"details":"Pretty simple",
"hint":"There is nothing you can do.",
"code":"P0001"
}Note
Keep in mind that RAISE EXCEPTION will abort the transaction and rollback all changes. If you don't want this, you can instead use the :ref:`response.status GUC <guc_resp_status>`.
One way to customize the HTTP status code is by raising particular exceptions according to the PostgREST :ref:`error to status code mapping <status_codes>`. For example, RAISE insufficient_privilege will respond with HTTP 401/403 as appropriate.
For even greater control of the HTTP status code, raise an exception of the PTxyz type. For instance to respond with HTTP 402, raise 'PT402':
RAISE sqlstate 'PT402' using
message = 'Payment Required',
detail = 'Quota exceeded',
hint = 'Upgrade your plan';Returns:
HTTP/1.1 402 Payment Required
Content-Type: application/json; charset=utf-8
{"hint":"Upgrade your plan","details":"Quota exceeded"}PostgREST translates PostgreSQL error codes into HTTP status as follows:
| PostgreSQL error code(s) | HTTP status | Error description |
|---|---|---|
| 08* | 503 | pg connection err |
| 09* | 500 | triggered action exception |
| 0L* | 403 | invalid grantor |
| 0P* | 403 | invalid role specification |
| 23503 | 409 | foreign key violation |
| 23505 | 409 | uniqueness violation |
| 25006 | 405 | read only sql transaction |
| 25* | 500 | invalid transaction state |
| 28* | 403 | invalid auth specification |
| 2D* | 500 | invalid transaction termination |
| 38* | 500 | external routine exception |
| 39* | 500 | external routine invocation |
| 3B* | 500 | savepoint exception |
| 40* | 500 | transaction rollback |
| 53* | 503 | insufficient resources |
| 54* | 413 | too complex |
| 55* | 500 | obj not in prerequisite state |
| 57* | 500 | operator intervention |
| 58* | 500 | system error |
| F0* | 500 | config file error |
| HV* | 500 | foreign data wrapper error |
| P0001 | 400 | default code for "raise" |
| P0* | 500 | PL/pgSQL error |
| XX* | 500 | internal error |
| 42883 | 404 | undefined function |
| 42P01 | 404 | undefined table |
| 42501 | if authenticated 403,
else 401
|
insufficient privileges |
| other | 400 |