Return error if post is already saved to IPFS

docs/openapi.yaml

@@ -17,8 +17,14 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/Status'
+        403:
+          description: Post does not belong to user or is not public
         404:
           description: Post not found
+        418:
+          description: IPFS integration is not enabled
+        422:
+          description: Post already saved to IPFS
   /api/v1/{status_id}/signature:
     get:
       summary: Sign post data with instance key
@@ -42,8 +48,14 @@ paths:
                   s:
                     type: string
                     example: '6a5cb313907cd3...'
+        403:
+          description: Post does not belong to user or is not public
         404:
           description: Post not found
+        418:
+          description: Ethereum integration is not enabled
+        422:
+          description: Post is not saved to IPFS
 
 components:
   parameters:

src/errors.rs

@@ -58,6 +58,9 @@ pub enum HttpError {
     #[error("operation not supported")]
     NotSupported,
 
+    #[error("{0}")]
+    OperationError(&'static str),
+
     #[error("internal error")]
     InternalError,
 }
@@ -94,6 +97,7 @@ impl ResponseError for HttpError {
             HttpError::PermissionError => StatusCode::FORBIDDEN,
             HttpError::NotFoundError(_) => StatusCode::NOT_FOUND,
             HttpError::NotSupported => StatusCode::IM_A_TEAPOT,
+            HttpError::OperationError(_) => StatusCode::UNPROCESSABLE_ENTITY,
             _ => StatusCode::INTERNAL_SERVER_ERROR,
         }
     }

src/mastodon_api/statuses/views.rs

@@ -319,9 +319,12 @@ async fn make_permanent(
     let db_client = &**get_database_client(&db_pool).await?;
     let current_user = get_current_user(db_client, auth.token()).await?;
     let mut post = get_post_by_id(db_client, &status_id).await?;
+    if post.ipfs_cid.is_some() {
+        return Err(HttpError::OperationError("post already saved to IPFS"));
+    };
     if post.author.id != current_user.id || !post.is_public() {
         // Users can only archive their own public posts
-        return Err(HttpError::NotFoundError("post"));
+        return Err(HttpError::PermissionError);
     };
     let ipfs_api_url = config.ipfs_api_url.as_ref()
         .ok_or(HttpError::NotSupported)?;
@@ -378,11 +381,11 @@ async fn get_signature(
     let post = get_post_by_id(db_client, &status_id).await?;
     if post.author.id != current_user.id || !post.is_public() {
         // Users can only tokenize their own public posts
-        return Err(HttpError::NotFoundError("post"));
+        return Err(HttpError::PermissionError);
     };
     let ipfs_cid = post.ipfs_cid
         // Post metadata is not immutable
-        .ok_or(HttpError::ValidationError("post is not immutable".into()))?;
+        .ok_or(HttpError::OperationError("post is not immutable"))?;
     let token_uri = get_ipfs_url(&ipfs_cid);
     let signature = create_mint_signature(
         contract_config,