YouTubeKit is a powerful Swift package to make requests to the YouTube API without having any API key.

DocC is available here.

Make sure that your implementation and usage of YouTubeKit are legal and make sure to tell the potential users of your app the eventual risks they encounter when they use your implementation.

1. Install the package to your Xcode project:
2. In the top menu go to File->Add Packages...
3. Enter the link of this repository: https://github.com/b5i/YouTubeKit (you may have to connect Xcode to your github account).
4. Click on Add Package.
5. Use it in your project by importing it: import YouTubeKit.

Please note that this is adapted from another iOS app and so is in constant developpement.

Here is a list of the default requests supported by YouTubeKit, all the informations you can get are:

• HomeScreenResponse -> get videos from the main page of YouTube, its Continuation is also available.

• SearchResponse -> get results for a text query, its Continuation is also available.

• SearchResponse.Restricted -> get Creative Commons copyrighted results for a text query.

• VideoInfosResponse -> get the infos of a video by ID.

• VideoInfosWithDownloadFormatsResponse -> get the infos of a video by ID and the DownloadFormats, consumes more bandwidth than VideoInfosResponse but has an array of DownloadFormat.

• MoreVideoInfosResponse to get various informations about a video (see documentation).

• TrendingVideosResponse to the trending tabs.

• AutoCompletionResponse -> get autoCompletion suggestions from a text query.

• ChannelInfosResponse -> get infos of a YouTube channel by its id.

  • Possiblity to fetch more infos about a channel like its Videos, Shorts, Directs, Playlists and their continuation.

• PlaylistInfosResponse -> get a playlist's informations and the videos it contains. Its Continuation is also available.

• AccountInfosResponse to get the informations about a YouTube account (using the cookies).
• AccountLibraryResponse to get the library of an account.
• AccountSubscriptionsFeedResponse to get the feed of the account's subscriptions.
• AccountSubscriptionsResponse to get the list of channel that the account is subscribed to.
• HistoryResponse and RemoveVideoFromHistroryResponse to get the history of an account and remove some videos of it.
• SubscribeChannelResponse and UnsubscribeChannelResponse.

• AllPossibleHostPlaylistsResponse to get all the playlists a video could be added to and if the video is already present inside.
• AddVideoToPlaylistResponse, CreatePlaylistResponse, DeletePlaylistResponse, MoveVideoInPlaylistResponse, RemoveVideoByIdFromPlaylistResponse and RemoveVideoFromPlaylistResponse to manage an account's playlists.
• LikeVideoResponse, DislikeVideoResponse and RemoveLikeFromVideoResponse.

• CreateCommentResponse to create a comment on a video.
• EditCommentResponse to edit a comment on a video.
• DeleteCommentResponse to delete a comment from a video.
• ReplyCommentResponse to create a reply to a comment.
• EditReplyCommandResponse to edit a reply to a comment on a video.
• DislikeCommentResponse to dislike a comment on a video.
• LikeCommentResponse to like a comment on a video.
• RemoveDislikeCommentResponse to remove a dislike from a comment.
• RemoveLikeCommentResponse to remove a like from a comment.
• CommentTranslationResponse to get the translation to a comment (does not require an account).

Every possible request within YouTubeKit conforms to the protocol YouTubeResponse, it contains a few useful methods:

• static var headersType is a static variable indicating the type of headers used to make the request, its documentation indicates which parameter to provide in order to make the request work.
• static var parametersValidationList is a static variable indicating if further processing and validation should be done on the parameters of the request. It can be validating that a videoId has the right format or simply that a parameter is provided.
• static func validateRequest(data: inout RequestData) throws is the method that will be called before sending the request over the internet. It will forward the errors given by the validators from parametersValidationList if there's some.
• static func decodeData(data: Data) throws -> Self is a static method used to decode some Data and give back in instance of the YouTubeResponse. Except for some special cases (if the raw data can't directly be converted into JSON for instance), you won't need to override the default implementation of this method.
• static func decodeJSON(json: JSON) throws -> Self is a static method used to decode some JSON and give back in instance of the YouTubeResponse, if the JSON does not represent a proper response it will return an empty response (only nils and empty arrays). Can throw a ResponseExtractionError if a critical extraction step fails.
• static func checkForErrors(json: JSON) throws is a static method that should be called before calling decodeJSON(json: JSON) to avoid trying to decode some JSON that represents an error. Except for some special cases (errors returned for this request are in a non-standart format), you won't need to override the default implementation.
• static func sendNonThrowingRequest() and static func sendThrowingRequest() are static methods that allows you to make requests, by using async await system or closures. Its usage will be precised in the following tutorial.

With YouTubeKit you can make a large variety of requests to the YouTube API, new request types are added often and you can even create your own in Custom requests/responses.

1. Make sure you have an instance of YouTubeModel, if not you can create one with

let YTM = YouTubeModel()

2. Define the request's data parameters, to get the demanded headers you can look at the definition of your YouTubeResponse.headersType it should describe which data to send. An example with a SearchResponse:

   a. Right click on the type of request and press Jump to definition, the SearchResponse.headersType is HeaderTypes.search.

   b. Its definition is

   /// Get search results.
   /// - Parameter query: Search query
   case search

   it means that you will have to provide a query for the request to work and give a relevant result.

   c. You will define the data parameters like this:

   let textQuery: String = "my super query"
   let dataParameters: [HeadersList.AddQueryInfo.ContentTypes : String] = [
       .query: textQuery
   ]

3. Execute the request with (e.g. a SearchResponse request)

SearchResponse.sendNonThrowingRequest(youtubeModel: YTM, data: dataParameters, result: { result, error in
  switch result {
  case .success(let response):
      /// Process here the result.
      print(response)
  case .failure(let error):
      /// If there is no result you should obtain an error explaining why there is none.
      print(error)
  }
})

you can also send the request without explicitly declaring dataParameters like this:

SearchResponse.sendNonThrowingRequest(youtubeModel: YTM, data: [.query: textQuery], result: { result in
  switch result {
  case .success(let response):
      /// Process here the result.
      print(response)
  case .failure(let error):
      /// If there is no result you should obtain an error explaining why there is none.
      print(error)
  }
})

and even use the async/throws API like this:

let result = try await SearchResponse.sendThrowingRequest(youtubeModel: YTM, data: [.query: textQuery])
switch result {
case .success(let response):
      /// Process here the result.
      print(response)
case .failure(let error):
      /// If there is no result you should obtain an error explaining why there is none.
      print(error)
}

YouTubeKit allows you to add an account's cookies into the requests by following those steps:

1. Define the cookies variable in your YouTubeModel:

let YTM = YouTubeModel()
YTM.cookies = "myCookies"

2. If you want to always use cookies when making requests you can opt to set the alwaysUseCookies of the YouTubeModel like so:

let YTM = YouTubeModel()
YTM.cookies = "myCookies"
YTM.alwaysUseCookies = true

3. You can also choose to use cookies by request by specifying the useCookies parameter present in every request function.

YouTubeKit has a built-in way to actively debug requests/responses at runtime.

1. For that, create your type of RequestsLogger and add it to the logger property of your YouTubeModel.

class Logger: RequestsLogger {
    var loggedTypes: [any YouTubeResponse.Type]? = nil

    var logs: [YouTubeKit.RequestLog] = []
            
    var isLogging: Bool = false
    
    var maximumCacheSize: Int? = nil
}
        
let logger = Logger()
        
YTM.logger = logger

2. Enable logging by calling the startLogging method of your logger:

logger.startLogging()

3. A full log of every request that has finished when logger.isLogging is true is stored in logger.logs by chronological order. Be aware that enabling logging can consume a lot of RAM as the logger stores a lot of raw informations. Therefore, make sure that you regularly clear the logger.logs using logger.clearLogs, disable logging when it's not needed or set a reasonable cache limit using logger.setCacheSize().

A lot of structures and protocol have custom request calls (shortcuts to various YouTubeResponse), here is a few examples:

1. `YouTubeVideo` (`YTVideo` conforms to it) has:

    1. `fetchStreamingInfos` that can be used to retrieve the basic streaming data.
    
    2. `fetchStreamingInfosWithDownloadFormats` that is the same as `fetchStreamingInfos` but it includes the download formats (all the different video/audio formats you can stream/download the video).
    
    3. `fetchMoreInfos` that can be used to retrieve more infos about the video (recommended videos, description with chapters and links, and more!).
    
    4. `likeVideo`, `dislikeVideo`, `removeLikeFromVideo`.
    
    5. `fetchAllPossibleHostPlaylists`
    
2. `YouTubeChannel` (`YTChannel`and `YTLittleChannelInfos` are conform to it) has:

    1. `fetchInfos` that can be used to retrieve various informations about the channel.
    
3. `ContinuableResponse` (`HomeScreenResponse`, `SearchResponse`, `PlaylistInfosResponse` are conform to it) has:

    1. `mergeContinuation` to merge the continuations easily.
    
    2. `fetchContinuation` to get those continuations.
    
4. `HistoryResponse` has `removeVideo` that can be used to remove a video from the history.

To create custom headers and so custom request/response function, you have to:

1. Append the function that is used to generate the HeadersList in YouTubeModel.customHeadersFunctions, e.g

let YTM = YouTubeModel()
let myCustomHeadersFunction: () -> HeadersList = {
    HeadersList(
        url: URL(string: "https://www.myrequesturl.com")!,
        method: .POST,
        headers: [
            .init(name: "Accept", content: "*/*"),
            .init(name: "Accept-Encoding", content: "gzip, deflate, br"),
            .init(name: "Accept-Language", content: "\(YTM.selectedLocale);q=0.9"),
        ],
        addQueryAfterParts: [
            .init(index: 0, encode: true)
        ],
        httpBody: [
            "my query is: ",
            " and it is really cool!"
        ]
    )
}

YouTubeModel.shared.customHeadersFunctions["myHeadersID"] = myCustomHeadersFunction

2. Create the response that is conform to the YouTubeResponse protocol, e.g

/*
We imagine that the JSON is of the form:
{
  "name": "myName",
  "surname": "mySurname"
}
*/


/// Struct representing a getNameAndSurname response.
public struct NameAndSurnameResponse: YouTubeResponse {
    public static let headersType: HeaderTypes = .customHeaders("myHeadersID") //<- the myHeadersID has to be the same as the one you defined in step 1!
    
    public static let parametersValidationList: ValidationList = [:] // we don't need any validators here as there's no parameters to provide.
    
    /// String representing a name.
    public var name: String = ""
    
    /// String representing a surname.
    public var surname: String = ""
    
    public static func decodeJSON(json: JSON) -> NameAndSurnameResponse {
        /// Initialize an empty response.
        var nameAndSurnameResponse = NameAndSurnameResponse()
                
        nameAndSurnameResponse.name = json["name"].stringValue
        nameAndSurnameResponse.surname = json["surname"].stringValue
        
        return nameAndSurnameResponse
    }
}

3. And to exectute it you just have to call func sendRequest( youtubeModel: YouTubeModel, data: [HeadersList.AddQueryInfo.ContentTypes : String], result: @escaping (Result<ResponseType, Error>) -> () ) e.g,

/// We continue with our example:
NameAndSurnameResponse.sendNonThrowingRequest(youtubeModel: YTM, data: [:], result: { result in
    switch result {
    case .success(let response):
        /// Process here the result.
        print(response)
    case .failure(let error):
        /// If there is no result you should obtain an error explaining why there is none.
        print(error)
    }
})

Note: you would include in the request the parameters if needed like: query, browseId or anything like this to put in the body of the request to send.

This category lists solutions to problems you might encounter with YouTubeKit.

• Error Domain=NSURLErrorDomain Code=-1003 "A server with the specified hostname could not be found."

  This issue can be resolved by enabling the Outgoing Connections (Client) in the Signing & Capabilities category of your project's target in Xcode.

• The download speed is very low when downloading an audio-only DownloadFormat: this issue can be resolved by adding the range: bytes=0-(CONTENT_LENGHT_BYTES) HTTP header to your URLRequest (e.g. request.addValue("bytes=0-\(myDownloadFormat.contentLength ?? "")", forHTTPHeaderField: "range")).

• The result of a request is empty: this issue could be caused by the locale that could be in the wrong format. Make sure that your YouTubeModel.selectedLocale is like en-US.

Thanks to the SwiftyJSON library for facilitating the JSON extraction!

Copyright (c) 2014 - 2017 Ruoyu Fu, Pinglin Tang

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