Include example backend implementation for the connect feature

config/examples/connect_backend_go/README.md

@@ -0,0 +1,17 @@
+# connect-backend-go
+
+Example Golang backend for Pgweb Connect feature
+
+## Usage
+
+Run the backend:
+
+```bash
+go run main.go
+```
+
+Configure pgweb:
+
+```bash
+pgweb --sessions --connect-backend=http://localhost:4567 --connect-token=test
+```

config/examples/connect_backend_go/main.go

@@ -0,0 +1,52 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"log"
+	"net/http"
+)
+
+type BackendRequest struct {
+	Resource string            `json:"resource"`
+	Token    string            `json:"token"`
+	Headers  map[string]string `json:"headers"`
+}
+
+type BackendResponse struct {
+	DatabaseURL string `json:"database_url"`
+}
+
+func main() {
+	resources := map[string]string{
+		"id1": "postgres://localhost:5432/db1?sslmode=disable",
+		"id2": "postgres://localhost:5432/db2?sslmode=disable",
+		"id3": "postgres://localhost:5432/db3?sslmode=disable",
+	}
+
+	http.HandleFunc("/", func(rw http.ResponseWriter, req *http.Request) {
+		backendReq := BackendRequest{}
+
+		if err := json.NewDecoder(req.Body).Decode(&backendReq); err != nil {
+			rw.WriteHeader(400)
+			fmt.Fprintf(rw, "error while parsing request: %v", err)
+			return
+		}
+
+		res, ok := resources[backendReq.Resource]
+		if !ok {
+			rw.WriteHeader(404)
+			return
+		}
+
+		resp := BackendResponse{
+			DatabaseURL: res,
+		}
+
+		json.NewEncoder(rw).Encode(resp)
+	})
+
+	if err := http.ListenAndServe(":4567", nil); err != nil {
+		log.Fatal(err)
+	}
+}