OCTClient.h

//
//  OCTClient.h
//  OctoKit
//
//  Created by Josh Abernathy on 3/6/12.
//  Copyright (c) 2012 GitHub. All rights reserved.
//

#import <Foundation/Foundation.h>
#import <SystemConfiguration/SystemConfiguration.h>

#if __IPHONE_OS_VERSION_MIN_REQUIRED
	#import <MobileCoreServices/MobileCoreServices.h>
#else
	#import <CoreServices/CoreServices.h>
#endif

#import <AFNetworking/AFNetworking.h>

@class OCTServer;
@class OCTUser;
@class RACSignal;

// The domain for all errors originating in OCTClient.
extern NSString * const OCTClientErrorDomain;

// A request was made to an endpoint that requires authentication, and the user
// is not logged in.
extern const NSInteger OCTClientErrorAuthenticationFailed;

// The authorization request requires a two-factor authentication one-time
// password.
extern const NSInteger OCTClientErrorTwoFactorAuthenticationOneTimePasswordRequired;

// The user attempted to authenticate with an OAuth token (like a Personal
// Access Token), when the endpoint actually requires a password.
extern const NSInteger OCTClientErrorTokenAuthenticationUnsupported;

// The server is refusing to process the request because of an
// authentication-related issue (HTTP error 403).
//
// Often, this means that there have been too many failed attempts to
// authenticate. Even a successful authentication will not work while this error
// code is being returned. The only recourse is to stop trying and wait for
// a bit.
extern const NSInteger OCTClientErrorRequestForbidden;

// The request was invalid (HTTP error 400).
extern const NSInteger OCTClientErrorBadRequest;

// The server refused to process the request (HTTP error 422).
//
// Among other reasons, this might be sent if one of the
// -requestAuthorizationWithPassword: methods is given an invalid client ID or
// secret.
extern const NSInteger OCTClientErrorServiceRequestFailed;

// There was a problem connecting to the server.
extern const NSInteger OCTClientErrorConnectionFailed;

// JSON parsing failed, or a model object could not be created from the parsed
// JSON.
extern const NSInteger OCTClientErrorJSONParsingFailed;

// The server is too old or new to understand our request.
extern const NSInteger OCTClientErrorUnsupportedServer;

// The server scheme is unsupported.
extern const NSInteger OCTClientErrorUnsupportedServerScheme;

// The GitHub login page could not be opened in a web browser.
//
// This error only affects +signInToServerUsingWebBrowser:scopes:.
extern const NSInteger OCTClientErrorOpeningBrowserFailed;

// There was a problem establishing a secure connection, although the server is
// reachable.
extern const NSInteger OCTClientErrorSecureConnectionFailed;

// A user info key associated with the NSURL of the request that failed.
extern NSString * const OCTClientErrorRequestURLKey;

// A user info key associated with an NSNumber, indicating the HTTP status code
// that was returned with the error.
extern NSString * const OCTClientErrorHTTPStatusCodeKey;

// A user info key associated with an NSString describing the scopes that were
// authorized for the OAuth token used in the failed request.
//
// This key won't be present if the request did not use OAuth.
extern NSString * const OCTClientErrorOAuthScopesStringKey;

// A user info key associated with an NSNumber-wrapped
// OCTClientOneTimePasswordMedium which indicates the medium of delivery for the
// one-time password required by the API. Only valid when the error's code is
// OCTClientErrorTwoFactorAuthenticationOneTimePasswordRequired.
extern NSString * const OCTClientErrorOneTimePasswordMediumKey;

/// The descriptive message returned from the API, e.g., "Validation Failed".
extern NSString * const OCTClientErrorDescriptionKey;

/// An array of specific message strings returned from the API, e.g.,
/// "No commits between joshaber:master and joshaber:feature".
extern NSString * const OCTClientErrorMessagesKey;

// The scopes for authorization. These can be bitwise OR'd together to request
// multiple scopes.
//
// OCTClientAuthorizationScopesPublicReadOnly   - Public, read-only access.
// OCTClientAuthorizationScopesUserEmail        - Read-only access to the user's
//                                                email.
// OCTClientAuthorizationScopesUserFollow       - Follow/unfollow access.
// OCTClientAuthorizationScopesUser             - Read/write access to profile
//                                                info. This includes OCTClientAuthorizationScopesUserEmail and
//                                                OCTClientAuthorizationScopesUserFollow
// OCTClientAuthorizationScopesRepositoryStatus - Read/write access to public
//                                                and private repository
//                                                commit statuses. This allows
//                                                access to commit statuses
//                                                without access to the
//                                                repository's code.
// OCTClientAuthorizationScopesPublicRepository - Read/write access to public
//                                                repositories and orgs. This
//                                                includes OCTClientAuthorizationScopesRepositoryStatus.
// OCTClientAuthorizationScopesRepository       - Read/write access to public
//                                                and private repositories and
//                                                orgs. This includes OCTClientAuthorizationScopesRepositoryStatus.
// OCTClientAuthorizationScopesRepositoryDelete - Delete access to adminable
//                                                repositories.
// OCTClientAuthorizationScopesNotifications    - Read access to the user's
//                                                notifications.
// OCTClientAuthorizationScopesGist             - Write access to the user's
//                                                gists.
// OCTClientAuthorizationScopesPublicKeyRead    - Read-only access to the user's public SSH keys.
// OCTClientAuthorizationScopesPublicKeyWrite   - Read/write access to the user's public SSH keys. This
//                                                includes OCTClientAuthorizationScopesPublicKeyRead.
// OCTClientAuthorizationScopesPublicKeyAdmin   - Full administrative access to the user's public SSH keys,
//                                                including permission to delete them. This includes
//                                                OCTClientAuthorizationScopesPublicKeyWrite.
typedef NS_OPTIONS(NSUInteger, OCTClientAuthorizationScopes) {
	OCTClientAuthorizationScopesPublicReadOnly = 1 << 0,

	OCTClientAuthorizationScopesUserEmail = 1 << 1,
	OCTClientAuthorizationScopesUserFollow = 1 << 2,
	OCTClientAuthorizationScopesUser = 1 << 3,

	OCTClientAuthorizationScopesRepositoryStatus = 1 << 4,
	OCTClientAuthorizationScopesPublicRepository = 1 << 5,
	OCTClientAuthorizationScopesRepository = 1 << 6,
	OCTClientAuthorizationScopesRepositoryDelete = 1 << 7,

	OCTClientAuthorizationScopesNotifications = 1 << 8,

	OCTClientAuthorizationScopesGist = 1 << 9,

	OCTClientAuthorizationScopesPublicKeyRead = 1 << 10,
	OCTClientAuthorizationScopesPublicKeyWrite = 1 << 11,
	OCTClientAuthorizationScopesPublicKeyAdmin = 1 << 12,
};

// The medium used to deliver the one-time password.
//
// OCTClientOneTimePasswordMediumSMS - Delivered via SMS.
// OCTClientOneTimePasswordMediumApp - Delivered via an app.
typedef NS_ENUM(NSInteger, OCTClientOneTimePasswordMedium) {
	OCTClientOneTimePasswordMediumSMS,
	OCTClientOneTimePasswordMediumApp,
};

// Represents a single GitHub session.
//
// Most of the methods on this class return a RACSignal representing a request
// made to the API. The returned signal will deliver its results on a background
// RACScheduler.
//
// To avoid hitting the network for a result that won't be used, **no request
// will be sent until the returned signal is subscribed to.** To cancel an
// in-flight request, simply dispose of all subscriptions.
//
// For more information about the behavior of requests, see
// -enqueueRequestWithMethod:path:parameters:resultClass: and
// -enqueueConditionalRequestWithMethod:path:parameters:notMatchingEtag:resultClass:,
// upon which all the other request methods are built.
@interface OCTClient : AFHTTPClient

// The active user for this session.
//
// This may be set regardless of whether the session is authenticated or
// unauthenticated, and will control which username is used for endpoints
// that require one. For example, this user's login will be used with
// -fetchUserEventsNotMatchingEtag:.
@property (nonatomic, strong, readonly) OCTUser *user;

// Whether this client supports authenticated endpoints.
//
// Note that this property does not specify whether the client has successfully
// authenticated with the server — only whether it will attempt to.
//
// This will be NO when `token` is `nil`.
@property (nonatomic, getter = isAuthenticated, readonly) BOOL authenticated;

// The OAuth access token that the client was initialized with.
//
// You should protect this token like a password. **Never** save it to disk in
// plaintext — use the keychain instead.
//
// This will be `nil` when the client is created using
// +unauthenticatedClientWithUser:.
@property (nonatomic, copy, readonly) NSString *token;

// Sets the HTTP User-Agent for the current app. This will have no effect on any
// clients that have already been created.
//
// This method is thread-safe.
//
// userAgent - The user agent to set. This must not be nil.
+ (void)setUserAgent:(NSString *)userAgent;

// Sets OAuth client information for the current app.
//
// If you only ever use +unauthenticatedClientWithUser:, you do not need to use this
// method. Otherwise, you must invoke this method before making any
// authentication requests.
//
// The information you provide here must match a registered OAuth application on
// the server. You can create a new OAuth application via
// https://github.com/settings/applications/new.
//
// Note that, because the `clientSecret` will be embedded in your app and sent
// over the user's internet connection, the secret isn't terribly secret. To
// help mitigate the risk of a web app stealing and using your `clientID` and
// `clientSecret`, set the Callback URL for your OAuth app to a URL you control.
// Even if this URL is never used by your app, this will prevent other apps
// from using your client ID and secret in a web flow.
//
// This method is thread-safe, and must be invoked before making any
// authentication requests. This will have no effect on any clients that have
// already been created.
//
// clientID     - The OAuth client ID for your application. This must not be
//                nil.
// clientSecret - The OAuth client secret for your application. This must not be
//                nil.
+ (void)setClientID:(NSString *)clientID clientSecret:(NSString *)clientSecret;

// Initializes the receiver to make requests to the given GitHub server.
//
// When using this initializer, the `user` property will not be set.
// +authenticatedClientWithUser:token: or +unauthenticatedClientWithUser:
// should typically be used instead.
//
// server - The GitHub server to connect to. This argument must not be nil.
//
// This is the designated initializer for this class.
- (id)initWithServer:(OCTServer *)server;

// Creates a client which can access any endpoints that don't require
// authentication.
//
// user - The active user. The `user` property of the returned client will be
//        set to this object. This must not be nil.
//
// Returns a new client.
+ (instancetype)unauthenticatedClientWithUser:(OCTUser *)user;

// Creates a client which will authenticate as the given user, using the given
// OAuth token.
//
// This method does not actually perform a login or make a request to the
// server. It only saves authentication information for future requests.
//
// user  - The user to authenticate as. The `user` property of the returned
//         client will be set to this object. This must not be nil.
// token - An OAuth token for the given user. This must not be nil.
//
// Returns a new client.
+ (instancetype)authenticatedClientWithUser:(OCTUser *)user token:(NSString *)token;

// Attempts to authenticate as the given user.
//
// Authentication is done using a native OAuth flow. This allows apps to avoid
// presenting a webpage, while minimizing the amount of time the client app
// needs the user's password.
//
// If `user` has two-factor authentication turned on and `oneTimePassword` is
// not provided, the authorization will be rejected with an error whose `code` is
// `OCTClientErrorTwoFactorAuthenticationOneTimePasswordRequired`. The behavior
// then depends on the `OCTClientOneTimePasswordMedium` that the user has set:
//
//  * If the user has chosen SMS as their authentication method, they will be
//    sent a one-time password _each time_ this method is invoked.
//  * If the user has chosen to use an app for authentication, they must open
//    their chosen app and use the one-time password it presents.
//
// You can then invoke this method again to request authorization using the
// one-time password entered by the user.
//
// **NOTE:** You must invoke +setClientID:clientSecret: before using this
// method.
//
// user            - The user to authenticate as. The `user` property of the
//                   returned client will be set to this object. This must not be nil.
// password        - The user's password. Cannot be nil.
// oneTimePassword - The one-time password to approve the authorization request.
//                   This may be nil if you have no one-time password to
//                   provide, which will usually be the case unless you've
//                   already requested authorization, `user` has two-factor
//                   authentication on, and the user has entered their one-time
//                   password.
// scopes          - The scopes to request access to. These values can be
//                   bitwise OR'd together to request multiple scopes.
// note            - A human-readable string to remind the user what this OAuth
//                   token is used for. May be nil.
// noteURL         - A URL to remind the user what the OAuth token is used for.
//                   May be nil.
// fingerprint     - A unique string to distinguish one authorization from
//                   others created for the same client ID and user. May be nil.
//
// Returns a signal which will send an OCTClient then complete on success, or
// else error. If the server is too old to support this request, an error will
// be sent with code `OCTClientErrorUnsupportedServer`.
+ (RACSignal *)signInAsUser:(OCTUser *)user password:(NSString *)password oneTimePassword:(NSString *)oneTimePassword scopes:(OCTClientAuthorizationScopes)scopes note:(NSString *)note noteURL:(NSURL *)noteURL fingerprint:(NSString *)fingerprint;

// Opens the default web browser to the given GitHub server, and prompts the
// user to sign in.
//
// Your app must be the preferred application for handling its URL callback, as set
// in your OAuth Application Settings). When the callback URL is opened using
// your app, you must invoke +completeSignInWithCallbackURL: in order for this
// authentication method to complete successfully.
//
// **NOTE:** You must invoke +setClientID:clientSecret: before using this
// method.
//
// server - The server that the user should sign in to. This must not be
//          nil.
// scopes - The scopes to request access to. These values can be
//          bitwise OR'd together to request multiple scopes.
//
// Returns a signal which will send an OCTClient then complete on success, or
// else error. If +completeSignInWithCallbackURL: is never invoked, the returned
// signal will never complete.
+ (RACSignal *)signInToServerUsingWebBrowser:(OCTServer *)server scopes:(OCTClientAuthorizationScopes)scopes;

// Makes a request to the given GitHub server to determine its metadata.
//
// server - The server to retrieve metadata for. This must not be nil.
//
// Returns a signal which will send an `OCTServerMetadata` object then complete on
// success, or else error. If the server is too old to support this request,
// an error will be sent with code `OCTClientErrorUnsupportedServer`.
+ (RACSignal *)fetchMetadataForServer:(OCTServer *)server;

// Notifies any waiting login processes that authentication has completed.
//
// This only affects authentication started with
// +signInToServerUsingWebBrowser:scopes:. Invoking this method will allow
// the originating login process to continue. If `callbackURL` does not
// correspond to any in-progress logins, nothing will happen.
//
// callbackURL - The URL that the app was opened with. This must not be nil.
+ (void)completeSignInWithCallbackURL:(NSURL *)callbackURL;

@end

@interface OCTClient (Requests)

// Creates a mutable URL request, which when sent will conditionally fetch the
// latest data from the server. If the latest data matches `etag`, nothing is
// downloaded and the call does not count toward the API rate limit.
//
// method          - The HTTP method to use in the request
//                   (e.g., "GET" or "POST").
// path            - The path to request, relative to the base API endpoint.
//                   This path should _not_ begin with a forward slash.
// parameters      - HTTP parameters to encode and send with the request.
// notMatchingEtag - An ETag to compare the server data against, previously
//                   retrieved from an instance of OCTResponse. If the content
//                   has not changed since, no new data will be fetched when
//                   this request is sent. This argument may be nil to always
//                   fetch the latest data.
//
// Returns an NSMutableURLRequest that you can enqueue using
// -enqueueRequest:resultClass:.
- (NSMutableURLRequest *)requestWithMethod:(NSString *)method path:(NSString *)path parameters:(NSDictionary *)parameters notMatchingEtag:(NSString *)etag;

// Enqueues a request to be sent to the server.
//
// This will automatically fetch all pages of the given endpoint. Each object
// from each page will be sent independently on the returned signal, so
// subscribers don't have to know or care about this pagination behavior.
//
// request       - The previously constructed URL request for the endpoint.
// resultClass   - A subclass of OCTObject that the response data should be
//                 returned as, and will be accessible from the parsedResult
//                 property on each OCTResponse. If this is nil, NSDictionary
//                 will be used for each object in the JSON received.
//
// Returns a signal which will send an instance of `OCTResponse` for each parsed
// JSON object, then complete. If an error occurs at any point, the returned
// signal will send it immediately, then terminate.
- (RACSignal *)enqueueRequest:(NSURLRequest *)request resultClass:(Class)resultClass;

@end