Implement some post endpoints for APIv4 (#5353)

* Implement POST /posts endpoint for APIv4

* Implement GET /channels/{channel_id}/posts endpoint for APIv4

* Implement GET /posts/{post_id} endpoint for APIv4

* Implement GET /posts/{post_id}/thread endpoint for APIv4

* Skip team get if it's a DM channel in handlePostEvents

api4/post.go

@@ -0,0 +1,119 @@
+// Copyright (c) 2017 Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package api4
+
+import (
+	"net/http"
+
+	l4g "github.com/alecthomas/log4go"
+	"github.com/mattermost/platform/app"
+	"github.com/mattermost/platform/model"
+	"github.com/mattermost/platform/utils"
+)
+
+func InitPost() {
+	l4g.Debug(utils.T("api.post.init.debug"))
+
+	BaseRoutes.Posts.Handle("", ApiSessionRequired(createPost)).Methods("POST")
+	BaseRoutes.Post.Handle("", ApiSessionRequired(getPost)).Methods("GET")
+	BaseRoutes.Post.Handle("/thread", ApiSessionRequired(getPostThread)).Methods("GET")
+	BaseRoutes.PostsForChannel.Handle("", ApiSessionRequired(getPostsForChannel)).Methods("GET")
+}
+
+func createPost(c *Context, w http.ResponseWriter, r *http.Request) {
+	post := model.PostFromJson(r.Body)
+	if post == nil {
+		c.SetInvalidParam("post")
+		return
+	}
+
+	post.UserId = c.Session.UserId
+
+	if !app.SessionHasPermissionToChannel(c.Session, post.ChannelId, model.PERMISSION_CREATE_POST) {
+		c.SetPermissionError(model.PERMISSION_CREATE_POST)
+		return
+	}
+
+	if post.CreateAt != 0 && !app.SessionHasPermissionTo(c.Session, model.PERMISSION_MANAGE_SYSTEM) {
+		post.CreateAt = 0
+	}
+
+	rp, err := app.CreatePostAsUser(post)
+	if err != nil {
+		c.Err = err
+		return
+	}
+
+	w.Write([]byte(rp.ToJson()))
+}
+
+func getPostsForChannel(c *Context, w http.ResponseWriter, r *http.Request) {
+	c.RequireChannelId()
+	if c.Err != nil {
+		return
+	}
+
+	if !app.SessionHasPermissionToChannel(c.Session, c.Params.ChannelId, model.PERMISSION_READ_CHANNEL) {
+		c.SetPermissionError(model.PERMISSION_READ_CHANNEL)
+		return
+	}
+
+	etag := app.GetPostsEtag(c.Params.ChannelId)
+
+	if HandleEtag(etag, "Get Posts", w, r) {
+		return
+	}
+
+	if list, err := app.GetPostsPage(c.Params.ChannelId, c.Params.Page, c.Params.PerPage); err != nil {
+		c.Err = err
+		return
+	} else {
+		w.Header().Set(model.HEADER_ETAG_SERVER, etag)
+		w.Write([]byte(list.ToJson()))
+	}
+}
+
+func getPost(c *Context, w http.ResponseWriter, r *http.Request) {
+	c.RequirePostId()
+	if c.Err != nil {
+		return
+	}
+
+	if !app.SessionHasPermissionToChannelByPost(c.Session, c.Params.PostId, model.PERMISSION_READ_CHANNEL) {
+		c.SetPermissionError(model.PERMISSION_READ_CHANNEL)
+		return
+	}
+
+	if post, err := app.GetSinglePost(c.Params.PostId); err != nil {
+		c.Err = err
+		return
+	} else if HandleEtag(post.Etag(), "Get Post", w, r) {
+		return
+	} else {
+		w.Header().Set(model.HEADER_ETAG_SERVER, post.Etag())
+		w.Write([]byte(post.ToJson()))
+	}
+}
+
+func getPostThread(c *Context, w http.ResponseWriter, r *http.Request) {
+	c.RequirePostId()
+	if c.Err != nil {
+		return
+	}
+
+	if !app.SessionHasPermissionToChannelByPost(c.Session, c.Params.PostId, model.PERMISSION_READ_CHANNEL) {
+		c.SetPermissionError(model.PERMISSION_READ_CHANNEL)
+		return
+	}
+
+	if list, err := app.GetPostThread(c.Params.PostId); err != nil {
+		c.Err = err
+		return
+	} else if HandleEtag(list.Etag(), "Get Post Thread", w, r) {
+		return
+	} else {
+		w.Header().Set(model.HEADER_ETAG_SERVER, list.Etag())
+		w.Write([]byte(list.ToJson()))
+	}
+}