Skip to main content

bluesky pub package Dart SDK Version

bluesky is a wrapper library that supports the endpoints defined in Lexicon for app.bsky.*.

All endpoints of the Bluesky API are supported. In addition, bluesky is built on atproto, so all features provided by atproto are built in.

info

If you are having trouble implementing RichText in the Bluesky API, check out bluesky_text!

Features ⭐

tip

See API Supported Matrix for a list of endpoints supported by bluesky.

Getting Started 💪

Install

tip

See the Install Package section for more details on how to install a package in your Dart and Flutter app.

With Dart:

dart pub add bluesky
dart pub get

With Flutter:

flutter pub add bluesky
flutter pub get

Import

Just by writing following one-line import, you can use all endpoints provided by bluesky.

import 'package:bluesky/bluesky.dart';

Instantiate Bluesky

You need to use Bluesky object to access most of the features supported by bluesky. And there are two ways to instantiate an Bluesky object.

As shown in the following example, the key point in instantiating Bluesky object is whether the endpoint you wish to use requires authentication.

tip

See API Supported Matrix for whether or not authentication is required for each endpoint.

If authentication is required, first create a session with the ATP server using your credentials with the .createSession function.

The credentials passed to the .createSession function should be your handle or email address as identifier and your password or app password as password.

Your credentials will be sent safely and securely to the ATP server when you execute the .createSession function. And it will return a Session object with an access token once authentication is complete.

You then do not need to be particularly aware of the contents of the retrieved Session object, just pass it to the .fromSession constructor of Bluesky to safely and securely create an instance of the Bluesky object.

Require Auth
import 'package:bluesky/bluesky.dart' as bsky;

Future<void> main() async {
// Let's authenticate here.
final session = await bsky.createSession(
identifier: 'YOUR_HANDLE_OR_EMAIL', // Like "shinyakato.dev"
password: 'YOUR_PASSWORD',
);

print(session);

// Just pass created session data.
final bluesky = bsky.Bluesky.fromSession(
session.data,
);
}

Or, it's very easy if authentication is not required , simply use the .anonymous() constructor.

Not Require Auth
import 'package:bluesky/bluesky.dart';

Future<void> main() async {
// Just call anonymous constructor.
final bluesky = Bluesky.anonymous();
}
info

See Session Management for more details about authentication.

Supported Services

bluesky supports following services.

PropertyClassLexicon
serverServerServicecom.atproto.server.*
identityIdentityServicecom.atproto.identity.*
repoRepoServicecom.atproto.repo.*
moderationModerationServicecom.atproto.moderation.*
syncSyncServicecom.atproto.sync.*
labelLabelServicecom.atproto.label.*
actorActorServiceapp.bsky.actor.*
feedFeedServiceapp.bsky.feed.*
notificationNotificationServiceapp.bsky.notification.*
graphGraphServiceapp.bsky.graph.*
unspeccedUnspeccedServiceapp.bsky.unspecced.*

Once an instance of the Bluesky object has been created, service endpoints can be used by accessing the property corresponding to each service as follows.

import 'package:bluesky/bluesky.dart' as bsky;

Future<void> main() async {
final session = await bsky.createSession(
identifier: 'YOUR_HANDLE_OR_EMAIL',
password: 'YOUR_PASSWORD',
);

// Just pass created session data.
final bluesky = bsky.Bluesky.fromSession(
session.data,
);

final timeline = await bluesky.feed.getTimeline();

print(timeline);
}
tip

See API Supported Matrix for a list of endpoints supported by bluesky.

Let's Implement

Okay then, let's try some endpoints!

The following example first authenticates the user against bsky.social, sends the post to Bluesky, and then deletes it using a reference to the created record.

import 'package:bluesky/bluesky.dart' as bsky;

Future<void> main() async {
final session = await bsky.createSession(
identifier: 'YOUR_HANDLE_OR_EMAIL',
password: 'YOUR_PASSWORD',
);

// Just pass created session data.
final bluesky = bsky.Bluesky.fromSession(
session.data,
);

// Create a record to specific service like Bluesky.
final strongRef = await bluesky.feed.post(
text: 'Hello, Bluesky!',
);

// And delete it.
await bluesky.repo.deleteRecord(uri: strongRef.data.uri);
}
tip

See API Support Matrix for all supported endpoints.

More Tips 🏄

Session Management

When using the AT Protocol API and Bluesky API, there are endpoints that requires user authentication, and an access token created when a user is authenticated is represented as a Session. Okay, the most important factor here is how to create a session.

First, use the .createSession function to create the most primitive session as follows.

import 'package:bluesky/bluesky.dart' as bsky;

Future<void> main() async {
final session = await bsky.createSession(
identifier: 'HANDLE_OR_EMAIL', // Like shinyakato.dev
password: 'PASSWORD', // App Password is recommended
);

print(session);
}

Then you can create Bluesky object from authenticated session.

import 'package:bluesky/bluesky.dart' as bsky;

Future<void> main() async {
final session = await bsky.createSession(
identifier: 'HANDLE_OR_EMAIL', // Like shinyakato.dev
password: 'PASSWORD', // App Password is recommended
);

print(session);

// You can create Bluesky object from authenticated session.
final bluesky = bsky.Bluesky.fromSession(session.data);

// Do something with bluesky
final did = await bluesky.identity.resolveHandle(handle: session.data.handle);
}

App Password

info

App passwords have most of the same abilities as the user's account password, however they're restricted from destructive actions such as account deletion or account migration. They are also restricted from creating additional app passwords. App passwords are of the form xxxx-xxxx-xxxx-xxxx.

So, it's strongly recommended that App Password be used for login in AT Protocol's services.

Given the above reason, a possible use case is for the application to determine if the password given by the user is an App Password. With bluesky, you can easily determine if a password is in App Password format by using the .isValidAppPassword function.

import 'package:bluesky/bluesky.dart' as bsky;

Future<void> main() async {
bsky.isValidAppPassword('xxxx-xxxx-xxxx-xxxx'); // => true
bsky.isValidAppPassword('xxxxxxxxxxxxxxxxxxx'); // => false
}

Other Than bsky.social

The endpoints provided by bluesky always access bsky.social by default. But as you know, certain services such as Bluesky, built on the AT Protocol, are distributed services. In other words, there must be a way to access services other than bsky.social as needed.

You can specify any service as follows.

import 'package:bluesky/bluesky.dart' as bsky;

Future<void> main() async {
final session = await bsky.createSession(
// Add this.
service: 'boobee.blue',

identifier: 'YOUR_HANDLE_OR_EMAIL',
password: 'YOUR_PASSWORD',
);

final bluesky = bsky.Bluesky.fromSession(
session.data,

// Add this.
service: 'boobee.blue',
);
}

De/Serialize

All objects representing JSON objects returned from the API provided by bluesky are generated using freezed and json_serializable. So, it allows for easy JSON-based de/serialize of these model objects based on the common contract between the fromJson and toJson methods.

For example, if you have the following code:

import 'package:bluesky/bluesky.dart';

Future<void> main() async {
final bluesky = Bluesky.anonymous();

// Just find the DID of `shinyakato.dev`
final did = await bluesky.identity.resolveHandle(
handle: 'shinyakato.dev',
);
}

Then you can deserialize DID object as JSON with toJson as follows:

print(did.toJson()); // => {did: did:plc:iijrtk7ocored6zuziwmqq3c}

And you can serialize JSON as DID object with fromJson as follows:

final json = did.toJson();

final serializedDID = DID.fromJson(json);

Thrown Exceptions

The following exceptions may be thrown as AT Protocol-related errors when using bluesky. The specification of this exception conforms to the following document from the official.

ExceptionDescriptionRetriable
XRPCExceptionParent class of all the following exception classes.
UnauthorizedExceptionThrown when a status code of 401 is returned from the ATP server. Indicating authentication failure.
RateLimitExceededExceptionThrown when a status code of 429 is returned from the ATP server. Indicating rate limits exceeded.
XRPCNotSupportedExceptionThrown when a status code of 1xx or 3xx is returned from the ATP server. Indicating unsupported error.
InvalidRequestExceptionThrown when a status code of 4xx is returned from the ATP server. Indicating client error.
InternalServerErrorExceptionThrown when a status code of 5xx is returned from the ATP server. Indicating server error.

Also, the following exceptions may be thrown due to temporary network failures.

ExceptionDescriptionRetriable
SocketExceptionThrown when a socket operation fails.
TimeoutExceptionThrown when a scheduled timeout happens while waiting for an async result.
info

Exceptions with Retriable set to ✅ are subject to automatic retry. Exceptions with ❌ cannot be retried.

Rate Limits

As with Web APIs in general, there is a rate limit for the AT Protocol and Bluesky API. The main purpose of setting a rate limit for the API is to prevent excessive requests to the server due to API abuse and to discourage spammy behavior.

Rate limits in the AT Protocol are defined in a common specification for the protocol and are set and you can easily access this information as follows.

import 'package:bluesky/bluesky.dart' as bsky;

Future<void> main() async {
final bluesky = bsky.Bluesky.fromSession(await _session);

final response = await bluesky.feed.getTimeline();

// This is rate limit!
print(response.rateLimit);

final rateLimit = response.rateLimit;

// Available properties.
print(rateLimit.limitCount);
print(rateLimit.remainingCount);
print(rateLimit.resetAt);
print(rateLimit.policy);

// When you need to handle rate limits.
print(rateLimit.isExceeded);
print(rateLimit.isNotExceeded);

// It waits until the rate limit is reset based on resetAt.
// If the rate limit is not exceeded, return immediately.
await rateLimit.waitUntilReset();
}

As in the example above, the rate limits when using bluesky are always accessible from XRPCResponse. In more detail, rate limit information is read from the HTTP response headers returned by the ATP server and can be accessed via the rateLimit property of the XRPCResponse as a RateLimit object.

The following properties are available from the RateLimit object, which are needed to determine the rate limit for the application.

PropertyHTTP HeaderDescription
limitCountRateLimit-LimitMaximum number of allowed requests.
remainingCountRateLimit-RemainingNumber of requests that can still be made.
resetAtRateLimit-ResetThe time when the rate limit will reset.
policyRateLimit-PolicyThe rate limit policy being applied like 100;w=300.

The properties for each rate limit as shown in the table above are very intuitive and easy to understand.

Slightly different from the HTTP Header information is the resetAt property. This is the date and time the rate limit is reset, not the number of seconds until the rate limit is reset. The date and time of the resetAt is calculated using the date and time when the response was created in GMT format in the date field given in the HTTP response header. In other words, the value of the resetAt property is the sum of date + RateLimit-Reset given in the HTTP response headers.

With all this out of the way, you can easily handle rate limits in the following way.

final rateLimit = response.rateLimit;

if (rateLimit.isExceeded) {
// It waits until the rate limit is reset based on resetAt.
await rateLimit.waitUntilReset();
}
caution

Rate limits per endpoint must be properly handled. If the request is sent again while the rate limit is exceeded, the HTTP status will always be 429 Too Many Requests and a RateLimitExceededException will be thrown.

tip

Some API endpoints have rate limits enabled, while others do not. This depends on the authentication method and the characteristics of each endpoint, but XRPCResponse always sets the RateLimit object, even for endpoints that do not have rate limiting enabled.

So you might ask what happens if you run the .isExceeded property with RateLimit taken from an endpoint that does not have a rate limit in effect? Nothing to worry about. The RateLimit object internally has a flag to indicate whether the rate limit is enabled or not.

That is, RateLimit object returned from an endpoint with no rate limit will be set as unlimited, and the isExceeded property will always return false.

Union Types

Since AT Protocol's Lexicon supports the Union type, there are several endpoints where multiple JSONs of different structures are returned at once. However, since Dart does not currently support Union as a language specification, there have been difficulties in marshaling JSON for this Union structure.

bluesky solves this problem neatly by using freezed to represent a pseudo-Union type. Besides it's type safe. And all the Union types provided by these atproto are .when(...) methods to handle them cleanly.

See, for example, Firehose API in the next section.

info

All Union types provided by bluesky always have the property unknown. This is because Union types not supported by bluesky cannot be converted to specific model objects when returned from a particular endpoint.

When an unknown event occurs, a raw JSON object that has not been marshalled into a specific model object is passed in the callback. This allows us to safely handle Union types with bluesky even if they are suddenly added officially, and also allows for more customization.

tip

Alternatively, you can handle these union objects more easily using pattern matching supported by Dart3. For example, if pattern matching is used, the processing of .when when using the Firehose API is replaced.

And all union objects have defined class names prefixed with U. So, if you want the Firehose API to handle only Commit and Handle events, you can use the USubscribedRepoCommit and USubscribedRepoHandle objects for pattern matching as follows.

import 'package:bluesky/bluesky.dart' as bsky;

Future<void> main() async {
final bluesky = bsky.Bluesky.anonymous();

final subscription = await bluesky.sync.subscribeRepos();

await for (final event in subscription.data.stream) {
// No need to use `.when` method.
switch (event) {
// Specify an union object prefixed with `U` as the case.
case bsky.USubscribedRepoCommit():
print(event.data.ops);
case bsky.USubscribedRepoHandle():
print(event.data.handle);
}
}
}

Firehose API

bluesky makes it easy to work with the powerful Firehose API.

The Firehose API in AT Protocol allows you to get all events that occur on a specific service, such as bsky.social, in real time. This powerful and long-lived API can be used to calculate statistics using real-time data, develop interesting interactive BOTs, etc.

Using bluesky to access the Firehose API is very simple, just execute the subscribeRepos method provided by the SyncService as shown in the following example. Also, user authentication is not required to access the Firehose API.

import 'package:bluesky/bluesky.dart';

Future<void> main() async {
// Authentication is not required.
final bluesky = Bluesky.anonymous();

final subscription = await bluesky.sync.subscribeRepos();

// Get events in real time.
await for (final event in subscription.data.stream) {
event.when(
// Occurs when account committed records, such as Post and Like in Bluesky.
commit: (data) {
// A single commit may contain multiple records.
for (final op in data.ops) {
switch (op.action) {
case RepoAction.create:
case RepoAction.update:
// Created/Updated AT URI and specific record.
print(op.uri);
print(op.record);

break;
case RepoAction.delete:
// Deleted AT URI.
print(op.uri);

break;
}
}
},

// Occurs when account changed handle.
handle: (data) {
// Updated handle.
print(data.handle);
print(data.did);
},

migrate: print,
tombstone: print,
info: print,
unknown: print,
);
}
}

The above example may seem a bit difficult, but the SubscribedRepo that can be retrieved in real-time from the Stream is of type Union, so .when(...) method can be used to easily handle each event.

In addition, bluesky can easily filter and retrieve only specific commit data from the Firehose API by using RepoCommitAdaptor.

import 'package:bluesky/bluesky.dart';

Future<void> main() async {
// Authentication is not required.
final bluesky = Bluesky.anonymous();

final subscription = await bluesky.sync.subscribeRepoUpdates();

// Use `RepoCommitAdaptor`.
final repoCommitAdaptor = RepoCommitAdaptor(
// Occurs only when post record is created.
onCreatePost: (data) {
print(data.uri);
print(data.record);
},
// Occurs only when profile record is updated.
onUpdateProfile: (data) {
print(data.uri);
print(data.record);
},
// Occurs only when follow record is deleted.
onDeleteFollow: (data) {
print(data.uri);
},
);

await for (final event in subscription.data.stream) {
event.when(
commit: repoCommitAdaptor.execute, // Execute like this.
handle: print,
migrate: print,
tombstone: print,
info: print,
unknown: print,
);
}
}
info

For more details about Firehose API, you can check this article.

Timeout Duration

When using the Bluesky object for API communication, the default timeout period is set to 30 seconds. This means that by default, a TimeoutException will be thrown if API communication takes longer than 30 seconds.

However, depending on system requirements, it may be necessary to set a time shorter than 30 seconds or even longer.

In that case, when creating an instance of the Bluesky object, the timeout period can be specified as follows.

import 'package:bluesky/bluesky.dart';

Future<void> main() async {
final bluesky = Bluesky.anonymous(
// Add this.
timeout: Duration(seconds: 20),
);
}

Advanced Built-In Retry

bluesky has an advanced retry feature using the Exponential BackOff And Jitter algorithm.

The reason why retry processing is so important in API communication is because the nature of the process of communicating with external servers means that there is always the possibility of temporary errors, such as network failures. In the event of a network failure, rather than throwing an exception and terminating the process, waiting for a while and retrying the process will often work.

And the algorithm is also important when retrying. This is because if the retry algorithm is simply one that waits and retries every fixed period of time, multiple retry requests will be sent to the server simultaneously before the temporary network failure is resolved. This condition will cause the server, which is temporarily out of shape, to generate even more heat.

The Exponential BackOff And Jitter used by bluesky solves this problem. bluesky uses a sophisticated algorithm with random numbers to distribute the load on the server while improving the probability of success on retries.

note

Jitter means random number.

You can use this retry features as follows.

import 'package:bluesky/bluesky.dart';

Future<void> main() async {
final bluesky = Bluesky.anonymous(
// Add this.
retryConfig: RetryConfig(
// Required.
// You can set count of attempts.
maxAttempts: 3,

// Optional.
// Jitter can be specified as you want.
jitter: Jitter(
maxInSeconds: 10,
minInSeconds: 5,
),

// Optional.
// You can define the events that occur when Retry is executed.
onExecute: (event) => print(
'Retry after ${event.intervalInSeconds} seconds...'
'[${event.retryCount} times]',
),
),
);
}

Then it retries:

  • When the status code of the response returned from ATP server is 5xx
  • When the network is temporarily lost and a SocketException is thrown
  • When communication times out temporarily and a TimeoutException is thrown

Lexicon/Object IDs

Some objects returned from AT Protocol's and Bluesky API are identified by IDs defined in Lexicon. The ID defined in Lexicon is also very important when sending a request to the API server.

bluesky provides all the IDs defined in Lexicon for com.atproto.* and app.bsky.* as constants, and it can be easily used from package:bluesky/ids.dart as follows.

import 'package:bluesky/ids.dart' as ids;

void main() {
// `blob`
ids.blob;
// `com.atproto.sync.subscribeRepos#commit`
ids.comAtprotoSyncSubscribeReposCommit;

// `app.bsky.feed.like`
ids.appBskyFeedLike;
// `app.bsky.feed.defs#reasonRepost`
ids.appBskyFeedDefsReasonRepost;
}
note

These ID constants are automatically maintained when a new Lexicon is officially added. See script.

Pagination

Pagination in the AT Protocol is designed to be performed using cursor. cursor is a string indicating the beginning of the next page, and is returned by the ATP server if the next page exists.

note

For more details about design of pagination and cursor in the AT Protocol, see official.

bluesky also follows the common design of AT Protocol and allows paging by using cursor. It can be easily implemented as in the following example.

import 'package:bluesky/bluesky.dart' as bsky;

Future<void> main() async {
final bluesky = bsky.Bluesky.fromSession(await _session);

// Pagination is performed on a per-cursor basis.
String? nextCursor;

do {
final actors = await bluesky.actor.searchActors(
term: 'alf',
cursor: nextCursor, // If null, it is ignored.
);

for (final actor in actors.data.actors) {
print(actor);
}

// Update pagination cursor.
nextCursor = actors.data.cursor;
} while (nextCursor != null); // If there is no next page, it ends.
}
tip

Endpoints that can be paged can be seen in this matrix.

This example is a very simple implementation, but it allows us to see pagination using bluesky.

Whenever a method corresponding to a pagination-available endpoint is executed, the cursor is always present in the root of the response data, like actors.data.cursor above. If the next page does not exist, cursor is basically null.

Unspecced Inputs

When using a POST endpoint with services other than AT Protocol or Bluesky Social, basically only expected inputs are allowed. For example, the input via in addition to text is not allowed for an endpoint where only the input text is expected.

However, AT Protocol and Bluesky Social allow these unexpected inputs to be posted and actually registered in the database. This is because Record in the AT Protocol are designed to be very generic, allowing registration and retrieval of fields other than the inputs and outputs defined in Lexicon.

caution

However, it's basically not possible to override the definition defined in Lexicon. For example, in the above example, if the text input is defined by Lexicon to be a string, the text value cannot be sent as a number or boolean value, but only string. If a structure or type different from the properties defined in Lexicon is detected, an InvalidRequestException is always thrown.

To include such unspecced inputs in a request using bluesky, implement with unspecced parameter as follows.

Post with Place Information
import 'package:bluesky/bluesky.dart' as bsky;

Future<void> main() async {
final bluesky = bsky.Bluesky.fromSession(await _session);

final ref = await bluesky.feed.post(
text: 'This is where I post from',

// Use this parameter.
unspecced: {
r'$place': {
'latitude': 40.730610,
'longitude': -73.935242,
}
},
);

print(ref);
}

Executing this code will register a following record.

{
"text": "This is where I post from",
"$type": "app.bsky.feed.post",
"createdAt": "2023-08-10T02:27:19.682542Z",
"$place": {
"latitude": 40.73061,
"longitude": -73.935242
}
}

As you can see, we were able to register a property that is not defined by Lexicon in app.bsky.feed.post.

danger

As in the example above, any object of any structure can be registered as a record, as long as it does not override the properties defined in the Lexicon supported by the service.

However, as you register your own properties, you should consider the possibility that they will be added to the official Lexicon in the future. If an official Lexicon property added in the future has the same name as a property you have registered, there is a possibility of name conflicts and system downtime for an unspecified number of clients. For example, if you registered place property and it's added to the official Lexicon in the future as a place with the same name, the client may not be able to process the data correctly due to structural inconsistencies.

So, make sure that the unique properties you register from the unspecced parameter are unique. To make the name of a property unique, the following methods are possible.

  • Prefix symbols such a $ (e.g. $place)
  • Prefix with the domain name you own (e.g. dev.shinyakato.place)

Moderation API

import 'package:bluesky/bluesky.dart' as bsky;
import 'package:bluesky/moderation.dart' as mod;

Future<void> main() async {
final bluesky = bsky.Bluesky.fromSession(await _session);

final preferences = await bluesky.actor.getPreferences();

// Moderation options based on user's preferences
final options = mod.getModerationOptions(
userDid: bluesky.session.did,
preferences: preferences.data.preferences,
);

// We call the appropriate moderation function for the content
// =

final profileModeration = mod.moderateProfile(profileView, options);
final postModeration = mod.moderatePost(postView, options);

// We then use the output to decide how to affect rendering
// =

if (postModeration.content.isFilter) {
// don't render in feeds or similar
// in contexts where this is disruptive (eg threads) you should ignore
// this and instead check blur
}

if (postModeration.content.isBlur) {
// render the whole object behind a cover
// (use postModeration.content.cause to explain)
if (postModeration.content.isNoOverride) {
// do not allow the cover the be removed
}
}

if (postModeration.content.isAlert) {
// render a warning on the content
//(use postModeration.content.cause to explain)
}

if (postModeration.embed.isBlur) {
// render the embedded media behind a cover
// (use postModeration.embed.cause to explain)
if (postModeration.embed.isNoOverride) {
// do not allow the cover the be removed
}
}

if (postModeration.embed.isAlert) {
// render a warning on the embedded media
//(use postModeration.embed.cause to explain)
}

if (postModeration.avatar.isBlur) {
// render the avatar behind a cover
}

if (postModeration.avatar.isAlert) {
// render an alert on the avatar
}
}

mod.ModerationSubjectProfile get profileView =>
mod.ModerationSubjectProfile.actor(
data: bsky.Actor(
did: 'did:web:bob.test',
handle: 'bob.test',
),
);

mod.ModerationSubjectPost get postView => mod.ModerationSubjectPost.post(
data: bsky.Post(
record: bsky.PostRecord(
text: 'Hello!',
createdAt: DateTime.now(),
),
author: bsky.Actor(
did: 'did:web:bob.test',
handle: 'bob.test',
),
uri: bsky.AtUri.parse('at://did:web:bob.test/test/fake'),
cid: 'fake',
indexedAt: DateTime.now(),
),
);