Add API method for generating post previews

https://codeberg.org/silverpill/mitra/issues/12

docs/openapi.yaml

@@ -710,9 +710,7 @@ paths:
               type: object
               properties:
                 status:
-                  description: |
-                    Text content of the post.
-                    Allowed HTML tags: a, br, pre, code, strong, em, p.
+                  description: Text content of the post.
                   type: string
                 content_type:
                   description: Media type of the post content.
@@ -751,6 +749,42 @@ paths:
                 $ref: '#/components/schemas/Status'
         400:
           description: Invalid post data
+  /api/v1/statuses/preview:
+    post:
+      summary: Preview new post.
+      security:
+        - tokenAuth: []
+      requestBody:
+        content:
+          application/json:
+            schema:
+              type: object
+              properties:
+                status:
+                  description: Text content of the post.
+                  type: string
+                content_type:
+                  description: Media type of the post content.
+                  type: string
+                  default: text/html
+                  enum:
+                    - text/html
+                    - text/markdown
+              required:
+                - status
+      responses:
+        200:
+          description: Preview generated.
+          content:
+            application/json:
+              schema:
+                type: object
+                properties:
+                  content:
+                    description: HTML-encoded post content.
+                    type: string
+        400:
+          description: Invalid post data.
   /api/v1/statuses/{status_id}:
     delete:
       summary: Delete post

src/mastodon_api/statuses/types.rs

@@ -149,6 +149,19 @@ pub struct StatusData {
     pub content_type: String,
 }
 
+#[derive(Deserialize)]
+pub struct StatusPreviewData {
+    pub status: String,
+
+    #[serde(default = "default_post_content_type")]
+    pub content_type: String,
+}
+
+#[derive(Serialize)]
+pub struct StatusPreview {
+    pub content: String,
+}
+
 #[derive(Deserialize)]
 pub struct TransactionData {
     pub transaction_id: String,

src/mastodon_api/statuses/views.rs

@@ -47,7 +47,13 @@ use super::helpers::{
     parse_microsyntaxes,
     PostContent,
 };
-use super::types::{Status, StatusData, TransactionData};
+use super::types::{
+    Status,
+    StatusData,
+    StatusPreview,
+    StatusPreviewData,
+    TransactionData,
+};
 
 #[post("")]
 async fn create_status(
@@ -161,6 +167,36 @@ async fn create_status(
     Ok(HttpResponse::Created().json(status))
 }
 
+#[post("/preview")]
+async fn preview_status(
+    auth: BearerAuth,
+    config: web::Data<Config>,
+    db_pool: web::Data<DbPool>,
+    status_data: web::Json<StatusPreviewData>,
+) -> Result<HttpResponse, HttpError> {
+    let db_client = &**get_database_client(&db_pool).await?;
+    get_current_user(db_client, auth.token()).await?;
+    let status_data = status_data.into_inner();
+    let content = match status_data.content_type.as_str() {
+        "text/html" => status_data.status,
+        "text/markdown" => {
+            markdown_lite_to_html(&status_data.status)
+                .map_err(|_| ValidationError("invalid markdown"))?
+        },
+        _ => return Err(ValidationError("unsupported content type").into()),
+    };
+    let PostContent { mut content, .. } = parse_microsyntaxes(
+        db_client,
+        &config.instance(),
+        content,
+    ).await?;
+    // Clean content
+    content = clean_content(&content)?;
+    // Return preview
+    let preview = StatusPreview { content };
+    Ok(HttpResponse::Ok().json(preview))
+}
+
 #[get("/{status_id}")]
 async fn get_status(
     auth: Option<BearerAuth>,
@@ -524,6 +560,7 @@ pub fn status_api_scope() -> Scope {
     web::scope("/api/v1/statuses")
         // Routes without status ID
         .service(create_status)
+        .service(preview_status)
         // Routes with status ID
         .service(get_status)
         .service(delete_status)