Simplify Go Endpoints + Add Tests (#120)

This MR represents a major refactor of the Go codebase, as well as introducing tests for the handlers. The MR also introduces an endpoint to shutdown or restart the Go server, which may be useful for clients who want to refresh the state of the plugin after checking out branches. Finally, this MR adds a contributing document for users who want to make feature changes.

cmd/reply.go

@@ -2,8 +2,6 @@ package main
 
 import (
 	"encoding/json"
-	"errors"
-	"fmt"
 	"io"
 	"net/http"
 	"time"
@@ -21,36 +19,18 @@ type ReplyResponse struct {
 	Note *gitlab.Note `json:"note"`
 }
 
-func (c *Client) Reply(r ReplyRequest) (*gitlab.Note, int, error) {
-
-	now := time.Now()
-	options := gitlab.AddMergeRequestDiscussionNoteOptions{
-		Body:      gitlab.String(r.Reply),
-		CreatedAt: &now,
-	}
-
-	note, res, err := c.git.Discussions.AddMergeRequestDiscussionNote(c.projectId, c.mergeId, r.DiscussionId, &options)
-
-	if err != nil {
-		return nil, res.Response.StatusCode, fmt.Errorf("Could not leave reply: %w", err)
-	}
-
-	return note, http.StatusOK, nil
-}
-
-func ReplyHandler(w http.ResponseWriter, r *http.Request) {
-	c := r.Context().Value("client").(Client)
+/* replyHandler sends a reply to a note or comment */
+func (a *api) replyHandler(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Content-Type", "application/json")
-
 	if r.Method != http.MethodPost {
-		w.Header().Set("Allow", http.MethodPost)
-		c.handleError(w, errors.New("Invalid request type"), "That request type is not allowed", http.StatusMethodNotAllowed)
+		w.Header().Set("Access-Control-Allow-Methods", http.MethodPost)
+		handleError(w, InvalidRequestError{}, "Expected POST", http.StatusMethodNotAllowed)
 		return
 	}
 
 	body, err := io.ReadAll(r.Body)
 	if err != nil {
-		c.handleError(w, err, "Could not read request body", http.StatusBadRequest)
+		handleError(w, err, "Could not read request body", http.StatusBadRequest)
 		return
 	}
 
@@ -59,21 +39,32 @@ func ReplyHandler(w http.ResponseWriter, r *http.Request) {
 	err = json.Unmarshal(body, &replyRequest)
 
 	if err != nil {
-		c.handleError(w, err, "Could not read JSON from request", http.StatusBadRequest)
+		handleError(w, err, "Could not read JSON from request", http.StatusBadRequest)
 		return
 	}
 
-	note, status, err := c.Reply(replyRequest)
+	now := time.Now()
+	options := gitlab.AddMergeRequestDiscussionNoteOptions{
+		Body:      gitlab.String(replyRequest.Reply),
+		CreatedAt: &now,
+	}
+
+	note, res, err := a.client.AddMergeRequestDiscussionNote(a.projectInfo.ProjectId, a.projectInfo.MergeId, replyRequest.DiscussionId, &options)
 
 	if err != nil {
-		c.handleError(w, err, "Could not send reply", status)
+		handleError(w, err, "Could not leave reply", http.StatusInternalServerError)
 		return
 	}
 
-	w.WriteHeader(status)
+	if res.StatusCode >= 300 {
+		handleError(w, GenericError{endpoint: "/reply"}, "Could not leave reply", res.StatusCode)
+		return
+	}
+
+	w.WriteHeader(http.StatusOK)
 	response := ReplyResponse{
 		SuccessResponse: SuccessResponse{
-			Message: fmt.Sprintf("Replied: %s", note.Body),
+			Message: "Replied to comment",
 			Status:  http.StatusOK,
 		},
 		Note: note,
@@ -81,6 +72,6 @@ func ReplyHandler(w http.ResponseWriter, r *http.Request) {
 
 	err = json.NewEncoder(w).Encode(response)
 	if err != nil {
-		c.handleError(w, err, "Could not encode response", http.StatusInternalServerError)
+		handleError(w, err, "Could not encode response", http.StatusInternalServerError)
 	}
 }