From 9ab9cdb176b8b4a191c65d58d60d89c99a8cde8f Mon Sep 17 00:00:00 2001
From: shockrah <alejandros714@protonmail.com>
Date: Wed, 21 Apr 2021 21:33:30 -0700
Subject: [PATCH] + db-lib::Channel::get added and Returns a
 Result<Option<Channel>> for simplicity This is really only for check if a
 particular channel exists for /messages/recent's backend

* Flattening db-lib::Message::last_n
SHould make code more readable as it now has a more linear flow

* api::Messages::recent_messages now 404's when a channel that doesn't exist is request
---
 json-api/db/src/channels.rs | 15 +++++++++++++++
 json-api/db/src/messages.rs | 37 +++++++++++++++++++++----------------
 json-api/src/messages.rs    |  3 +++
 3 files changed, 39 insertions(+), 16 deletions(-)

diff --git a/json-api/db/src/channels.rs b/json-api/db/src/channels.rs
index d6b0116..46adf69 100644
--- a/json-api/db/src/channels.rs
+++ b/json-api/db/src/channels.rs
@@ -14,6 +14,21 @@ pub const MAX_NAME_LEN: usize = 256;
 pub const MAX_DESCRIPTION_LEN: usize = 2048;
 
 impl Channel {
+    pub async fn get(p: &Pool, id: u64) -> Result<Option<Channel>, SqlError> {
+        let mut conn = p.get_conn().await?;
+        let q = "SELECT name, description, kind FROM channels WHERE id = :id";
+        let params = params!{"id" => id};
+        let row: Option<(String, Option<String>, i32)> =
+            conn.exec_first(q, params).await?;
+
+        if let Some(row) = row {
+            let chan = Channel { id, name: row.0, description: row.1, kind: row.2 };
+            Ok(Some(chan))
+        } else {
+            Ok(None)
+        }
+    }
+
     pub async fn filter(p: &Pool, kind: Integer) -> Result<Response<Self>, SqlError> {
         //! @returns -> on success   : Ok(Response::Set(Vec<Channel>))
         //! @throw   -> on sql fail  : Err(SqlError)
diff --git a/json-api/db/src/messages.rs b/json-api/db/src/messages.rs
index 1e9c7d7..6c3f327 100644
--- a/json-api/db/src/messages.rs
+++ b/json-api/db/src/messages.rs
@@ -10,7 +10,7 @@ use mysql_async::Error as SqlError;
 
 use crate::Response;
 use crate::{UBigInt, BigInt};
-use crate::{Message, UserMessage};
+use crate::{Channel, Message, UserMessage};
 use crate::common;
 
 use rand::RngCore;
@@ -218,22 +218,27 @@ impl Message {
     pub async fn last_n(p: &Pool, limit: i32, channel_id: u64) -> Result<Response<UserMessage>, SqlError> {
         if limit <= 0 || limit > 100 {
             return Ok(Response::RestrictedInput("Invalid \"limit\" value".into()))
-        } else {
-            // Reminder: if content_type is not text/plain then content will be empty
-            let q = " SELECT mem.name, msg.id, msg.time, msg.content, msg.content_type, msg.author_id 
-                FROM messages as msg
-                JOIN members as mem ON mem.id = msg.author_id
-                WHERE channel_id = :channel
-                ORDER BY id DESC LIMIT :limit";
-            let params = params!{"limit" => limit, "channel" => channel_id};
-            let mut conn = p.get_conn().await?;
-            let messages = conn.exec_map(q, params, |(name, id, time, content, content_type, author_id)| {
-                UserMessage {
-                    name, id, time, content, content_type, author_id, channel_id
-                }
-            }).await?;
-            return Ok(Response::Set(messages))
+        } 
+
+        // Explicitly return empty if the channel requested does not exist
+        if let None = Channel::get(p, channel_id).await? {
+            return Ok(Response::Empty)
         }
+
+        // Reminder: if content_type is not text/plain then content will be empty
+        let q = " SELECT mem.name, msg.id, msg.time, msg.content, msg.content_type, msg.author_id 
+            FROM messages as msg
+            JOIN members as mem ON mem.id = msg.author_id
+            WHERE channel_id = :channel
+            ORDER BY id DESC LIMIT :limit";
+        let params = params!{"limit" => limit, "channel" => channel_id};
+        let mut conn = p.get_conn().await?;
+        let messages = conn.exec_map(q, params, |(name, id, time, content, content_type, author_id)| {
+            UserMessage {
+                name, id, time, content, content_type, author_id, channel_id
+            }
+        }).await?;
+        return Ok(Response::Set(messages))
     }
 }
 
diff --git a/json-api/src/messages.rs b/json-api/src/messages.rs
index 1e3aa15..2eef93c 100644
--- a/json-api/src/messages.rs
+++ b/json-api/src/messages.rs
@@ -145,6 +145,9 @@ pub async fn recent_messages(pool: &Pool, response: &mut Response<Body>, params:
                     // 200
                     db::Response::Set(messages) => 
                         set_json_body(response, json!({"messages": messages})),
+                    // 404 - assuming the request channel does not exist
+                    db::Response::Empty =>
+                        *response.status_mut() = StatusCode::NOT_FOUND,
                     // 400
                     db::Response::RestrictedInput(msg) => {
                         *response.status_mut() = StatusCode::BAD_REQUEST;