A function to fetch a markdown post file in Firebase Storage from Cloud Function (old way).

firebase_functions_save_post.ts

/**
 * Save a project content
 * (with accessibility check).
 */
export const save = functions
    .region(cloudRegions.eu)
    .https
    .onCall(async (data) => {
      const projectId: string = data.projectId;
      const jwt: string = data.jwt;
      const content: string = data.content;

      if (!content || !projectId) {
        throw new functions.https.HttpsError(
            "invalid-argument",
            `The function must be called 
         with two (string) arguments "projecId": 
     the project to save, "content": the project's content.`,
        );
      }

      // Check this helper function in its dedicated gist.
      // [firebase_functions_helper_post_acl.ts](https://gist.github.com/rootasjey/6b8594cd4da10822c5029a6997f1b8c6)
      await checkAccessControl({projectId, jwt});

      const projectFile = storage
          .bucket()
          .file(`blog/projects/${projectId}/post.md`);

      try {
        await projectFile.save(content);
        return {success: true};
      } catch (error) {
        return {success: false, error: error};
      }
    });