(feat): Add request.set_headers and request.prepend_headers

src/gleam/http/request.gleam

@@ -95,6 +95,34 @@ pub fn prepend_header(
   Request(..request, headers: headers)
 }
 
+/// Set a request's headers using a list.
+///
+/// Similar to `set_header` but for setting more than a single header at once.
+/// Existing headers on the request will be replaced.
+pub fn set_headers(
+  request: Request(body),
+  headers: List(#(String, String)),
+) -> Request(body) {
+  let new_headers =
+    list.fold(headers, [], fn(acc, header) {
+      list.key_set(acc, string.lowercase(header.0), header.1)
+    })
+  Request(..request, headers: new_headers)
+}
+
+/// Prepend the request header with the given key/values.
+///
+/// Similar to `prepend_header` but for prepending multiple key/values at once.
+/// If a header already exists it prepends another header with the same key.
+pub fn prepend_headers(
+  request: Request(body),
+  headers: List(#(String, String)),
+) -> Request(body) {
+  list.fold(headers, request, fn(acc, header) {
+    prepend_header(acc, header.0, header.1)
+  })
+}
+
 // TODO: record update syntax, which can't be done currently as body type changes
 /// Set the body of the request, overwriting any existing body.
 ///

test/gleam/http/request_test.gleam

@@ -362,6 +362,71 @@ pub fn set_request_header_lowercases_key_test() {
   |> should.equal([#("uppercase_gleam", "awesome")])
 }
 
+pub fn set_req_headers_test() {
+  let request =
+    Request(
+      method: http.Get,
+      headers: [],
+      body: Nil,
+      scheme: http.Https,
+      host: "example.com",
+      port: None,
+      path: "/",
+      query: None,
+    )
+    |> request.set_headers([
+      #("gleam", "awesome"),
+      #("ocaml", "also pretty cool"),
+    ])
+
+  request.headers
+  |> should.equal([#("gleam", "awesome"), #("ocaml", "also pretty cool")])
+
+  // Set updates existing
+  let request =
+    request
+    |> request.set_headers([#("gleam", "the best")])
+
+  request.headers
+  |> should.equal([#("gleam", "the best")])
+}
+
+pub fn set_request_headers_maintains_value_casing_test() {
+  let request =
+    Request(
+      method: http.Get,
+      headers: [],
+      body: Nil,
+      scheme: http.Https,
+      host: "example.com",
+      port: None,
+      path: "/",
+      query: None,
+    )
+    |> request.set_headers([#("gleam", "UPPERCASE_AWESOME")])
+
+  request.headers
+  |> should.equal([#("gleam", "UPPERCASE_AWESOME")])
+}
+
+pub fn set_request_headers_lowercases_key_test() {
+  let request =
+    Request(
+      method: http.Get,
+      headers: [],
+      body: Nil,
+      scheme: http.Https,
+      host: "example.com",
+      port: None,
+      path: "/",
+      query: None,
+    )
+    |> request.set_headers([#("UPPERCASE_GLEAM", "awesome")])
+
+  request.headers
+  |> should.equal([#("uppercase_gleam", "awesome")])
+}
+
 pub fn prepend_req_header_test() {
   let headers = []
   let request =
@@ -401,6 +466,45 @@ pub fn prepend_req_header_test() {
   ])
 }
 
+pub fn prepend_req_headers_test() {
+  let headers = []
+  let request =
+    Request(
+      method: http.Get,
+      headers: headers,
+      body: Nil,
+      scheme: http.Https,
+      host: "example.com",
+      port: None,
+      path: "/",
+      query: None,
+    )
+    |> request.prepend_headers([#("answer", "42")])
+
+  request.headers
+  |> should.equal([#("answer", "42")])
+
+  let request =
+    request
+    |> request.prepend_headers([#("gleam", "awesome")])
+
+  // request should have two headers now
+  request.headers
+  |> should.equal([#("gleam", "awesome"), #("answer", "42")])
+
+  let request =
+    request
+    |> request.prepend_headers([#("gleam", "awesome")])
+
+  // request repeats the existing header
+  request.headers
+  |> should.equal([
+    #("gleam", "awesome"),
+    #("gleam", "awesome"),
+    #("answer", "42"),
+  ])
+}
+
 pub fn get_req_cookies_test() {
   request.new()
   |> request.prepend_header("cookie", "k1=v1; k2=v2")