Make fallback embed more generalised && bundle html templates in the binary

Author: ItsOnlyBinary

fallback-embed/fallback-embed-provider.go

@@ -0,0 +1,125 @@
+package fallbackembed
+
+import (
+	"encoding/json"
+	"errors"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"regexp"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// FallbackEmbed represents this package
+type FallbackEmbed struct {
+	data        *Data
+	httpClient  *http.Client
+	targetKey   string
+	providerURL string
+}
+
+// Data represents the data for FallbackEmbed providers
+type Data []struct {
+	Name     string  `json:"name"`
+	Patterns []Regex `json:"patterns"`
+}
+
+// New returns a FallbackEmbed object
+func New(providerURL, targetKey string) *FallbackEmbed {
+	obj := &FallbackEmbed{
+		httpClient: &http.Client{
+			Timeout: time.Second * 30,
+		},
+		providerURL: providerURL,
+		targetKey:   targetKey,
+	}
+
+	return obj
+}
+
+// ParseProviders parses the raw json obtained from noembed.com
+func (f *FallbackEmbed) ParseProviders(buf io.Reader) error {
+	data, err := ioutil.ReadAll(buf)
+	if err != nil {
+		return err
+	}
+
+	var providerData Data
+	err = json.Unmarshal(data, &providerData)
+	if err != nil {
+		return err
+	}
+
+	f.data = &providerData
+	return nil
+}
+
+// Get returns html string
+func (f *FallbackEmbed) Get(url string, width int, height int) (html string, err error) {
+	if !f.ValidURL(url) {
+		return
+	}
+
+	// Do replacements
+	reqURL := strings.Replace(f.providerURL, "{url}", url, 1)
+	reqURL = strings.Replace(reqURL, "{width}", strconv.Itoa(width), 1)
+	reqURL = strings.Replace(reqURL, "{height}", strconv.Itoa(height), 1)
+
+	var httpResp *http.Response
+	httpResp, err = f.httpClient.Get(reqURL)
+	if err != nil {
+		return
+	}
+	defer httpResp.Body.Close()
+
+	var body []byte
+	body, err = ioutil.ReadAll(httpResp.Body)
+	if err != nil {
+		return
+	}
+
+	// Try to parse json response
+	resp := make(map[string]interface{})
+	err = json.Unmarshal(body, &resp)
+	if err != nil {
+		return
+	}
+
+	// Check targetKey exists
+	if jsonVal, ok := resp[f.targetKey]; ok {
+		// Check targetVal is string
+		if htmlString, ok := jsonVal.(string); ok {
+			html = htmlString
+			return
+		}
+	}
+
+	err = errors.New("Failed to get target json key")
+	return
+}
+
+// ValidURL is used to test if a url is supported by noembed
+func (f *FallbackEmbed) ValidURL(url string) bool {
+	for _, entry := range *f.data {
+		for _, pattern := range entry.Patterns {
+			if pattern.Regexp.MatchString(url) {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+// Regex Unmarshaler
+type Regex struct {
+	regexp.Regexp
+}
+
+// UnmarshalText used to unmarshal regexp's from text
+func (r *Regex) UnmarshalText(text []byte) error {
+	reg, err := regexp.Compile(string(text))
+	r.Regexp = *reg
+	return err
+}

fileuploader.config.example.toml

@@ -45,11 +45,17 @@ MaxAge = "24h" # 1 day
 IdentifiedMaxAge = "168h" # 1 week
 CheckInterval = "5m"
 
-[Embed]
-TemplatePath = "templates/embed.html"
+[WebPreview]
+TemplatesDirectory = "templates"
 CacheMaxAge = "1h"
 CacheCleanInterval = "15m"
 
+# Fallback provider specific
+FallbackProviderDisabled = false
+FallbackProviderURL = "https://noembed.com/embed?url={url}"
+FallbackProviderFile = "fallback-providers.json"
+FallbackProviderJsonKey = "html"
+
 # If EXTJWT is supported by the gateway or network, a validated token with an account present (when
 # the user is authenticated to an irc services account) will use the IdentifiedMaxAge setting above
 # instead of the base MaxAge.

main.go

@@ -6,6 +6,8 @@ import (
 	"github.com/kiwiirc/plugin-fileuploader/server"
 )
 
+//go:generate go run ./scripts/generate-templates.go
+
 func main() {
 	var configPath = flag.String("config", "fileuploader.config.toml", "path to config file")
 	flag.Parse()

noembed/noembed.go

@@ -0,0 +1,27 @@
+package main
+
+import (
+	"io"
+	"io/ioutil"
+	"os"
+	"path"
+	"strings"
+)
+
+const templatesDir = "./templates"
+
+func main() {
+	files, _ := ioutil.ReadDir(templatesDir)
+
+	out, _ := os.Create(path.Join(templatesDir, "templates.go"))
+	out.Write([]byte("package templates\n\nvar Get = map[string]string{\n"))
+	for _, fileInfo := range files {
+		if strings.HasSuffix(fileInfo.Name(), ".html") {
+			out.Write([]byte(strings.TrimSuffix(fileInfo.Name(), ".html") + ": `"))
+			file, _ := os.Open(path.Join(templatesDir, fileInfo.Name()))
+			io.Copy(out, file)
+			out.Write([]byte("`,\n"))
+		}
+	}
+	out.Write([]byte("}\n"))
+}

scripts/generate-templates.go

@@ -46,13 +46,17 @@ type Config struct {
 	JwtSecretsByIssuer map[string]string
 	Loggers            []LoggerConfig
 
-	// Embed Provider
-	Embed struct {
-		TemplatePath       string
+	// WebPreview config options
+	WebPreview struct {
+		TemplatesDirectory string
 		CacheMaxAge        duration
 		CacheCleanInterval duration
-		ImageCachePath     string
-		ImageCacheMaxSize  uint64
+
+		// Fallback provider configuration
+		FallbackProviderDisabled bool
+		FallbackProviderURL      string
+		FallbackProviderFile     string
+		FallbackProviderJsonKey  string
 	}
 }