Post Bluesky entries including link preview card

bluesky_post.dart

import 'package:bluesky/atproto.dart';
import 'package:bluesky/bluesky.dart';
import 'package:bluesky/core.dart';
import 'package:bluesky_text/bluesky_text.dart';
import 'package:http/http.dart' as http;
import 'package:metadata_fetch/metadata_fetch.dart';

Future<void> postEntry(PostDataEntry postData, String username, String password) async {
  try {
    // Create the Bluesky session. As the login is done by username and password it is
    // suggested to create an app-specifc password, to avoid using your normal credentials
    final session = await createSession(
      identifier: username,
      password: password,
    );

    // Create the actual Bluesky object from the session
    final bluesky = Bluesky.fromSession(
      await session.data,
    );

    // Format the text to make links and tags clickable within your post
    final blueskyText = BlueskyText(postData.text);
    final facets = await blueskyText.entities.toFacets();

    // Post the content, including the card and your defined text
    final entry = await bluesky.feed.post(
      text: blueskyText.value,
      facets: facets.map(Facet.fromJson).toList(),
      embed: await fetchDataAndUploadMedia(bluesky, postData.url),
    );
    print(entry);
  } on UnauthorizedException catch (e) {
    print(e);
  } on XRPCException catch (e) {
    print(e);
  }
}

Future<Embed?> fetchDataAndUploadMedia(Bluesky bluesky, String url) async {
  // Fetch / extract web content
  final data = await MetadataFetch.extract(url);
  final title = data?.title;
  final description = data?.description;

  // Upload media to Bluesky
  Blob? blob = await fetchAndUploadImage(bluesky, data?.image);

  // If everything was fetched and the media upload was successful, return the formatted data
  if (title != null && description != null && blob != null) {
    return Embed.external(
      data: EmbedExternal(
        external: EmbedExternalThumbnail(
          uri: url,
          title: title,
          description: description,
          blob: blob,
        ),
      ),
    );
  }
  // If something went wrong, return null
  return null;
}

Future<Blob?> fetchAndUploadImage(Bluesky bluesky, String? imageUrl) async {
  if (imageUrl != null) {
    try {
      // Fetch the image from the web
      final uri = Uri.parse(imageUrl);
      final http.Response response = await http.get(uri);
      
      // Upload the image to Bluesky and return the blog, which is needed to create the post
      final uploadResponse = await bluesky.atproto.repo.uploadBlob(response.bodyBytes);
      return uploadResponse.data.blob;
    } catch (e) {
      print(e);
    }
  }
  // If something went wrong, return null
  return null;
}

class PostDataEntry {
  final String url;
  final String text;

  PostDataEntry({required this.url, required this.text});
}