SDEDownloadManager

Create a download manager with specified identifier.

After download manager is inited, it begins to load data in the background immediately.

Choose sort mode based on your usage scenario. SDEDownloadManager has two sort mode: manual and predefined mode. The two sort modes can switch to each other. Except for obvious sort difference, what’s difference between with two modes?

1. Download new file. In predefined mode, you just need to offer download URL, but in manual mode, you must offer its insert location in downloadList, which is [[String]] and is designed for UITableView/UICollectionView.
2. A section in UITableView with .plain style can’t be distinguished from last section if it doesn’t have a title, so in manual mode, you must offer a title.

Although you can switch between with two sort modes freely, switching from manual mode to predefined mode will lose all section titles, and switching from predefined mode to manual mode will integrate all tasks into one section with a placeholder title, so choose sort mode based on your usage scenario discreetly.

This method is synchronous, and it’s executed in current thread. Everytime app enter background, SDEDownloadManager calls this method automatically.

Data are splited into several parts and are saved separately, only changed part will be saved, so it has a good performance at the most time if data is not huge(like under 10000 records). You’d better test its performance in your environment.

Check whether specified download manager could be destoryed safely. This method returns true only when:

1. The specified download manager is existed in the database.
2. The specified download manager is not existed in the memory. Because of implementation of manager(identifier:manualMode:), once it’s called, returned manager is existed in the memory until app is exited.

Destroy underlying data of specified download manager, not includes live data if specified download manager exists in the memory already. You should call isDestoryableForManager(_:) to check whether specified download manager is destoryable before calling this method because destoryed data cannot be recovered.

Note: This method won’t delete downloaded files.

The unique identifier. Specify it in manager(identifier:manualMode:), if a SDEDownloadManager object with the identifier exists in the memory already, this methos return it directly.

A Boolean value indicating whether data is loaded. After a SDEDownloadManager object is inited, it loads data in the background. Usually it’s very soon to load data.

The current sort type of download list(read-only). The default value is .addTime.

sortType has five values: .manual, .addTime, .fileName, .fileSize, .fileType. They are classified as two modes: manual mode(.manual) and predefined mode(latter four types). For .manual type, you determine task locations; for latter four types, task locations are determined by sortType and sortOrder together.

Call sortListBy(type:order:) to switch between sort types.

.ascending or .descending. This property is ignored if sortType == .manual. The default value is .ascending.

You can call sortListBy(sortType:sortOrder:) to change sort order.

A URL string array includes all section titles for UITableView/UICollectionView.

URL strings of current all tasks.

A URL string array includes tasks to delete. Sorted by delete time and the head is the most recent deleted task.

A URL string array includes all unfinished tasks(not include task in toDeleteList). It’s dynamic: URL string will be removed from this list after its task is finished. Sorted by add time in downloadList and the head is the most recent added task.

A URL string set includes all tasks in downloadList.

A URL string set includes all tasks in the download manager: downloadList and toDeleteList.

Section count of downloadList.

Task count in the specified section.

Header title used in UITableView/UICollectionView.

Download a group of new files in predefined sort mode(sortType != .manual) and return locations of new files in downloadList immediately. If data is not loaded, this method will wait.

If current sortType is not .addTime, download mananger switch to .addTime automatically.

If downloadNewFileImmediately is false, this method just add a record, you can start the task by resumeTasks(_:successOrFailHandler:).

Insert an empty section as placeholder in manual sort mode(sortType == .manual) and return a Boolean value indicating whether insertion is successful. If data is not loaded, this method will wait.

Download a group of new files in manual sort mode(sortType == .manual), insert them in downloadList at the section which you specify, and return a Boolean value indicating whether insertion is successful immediately. downloadList is a two-dimensional string array: [[String]]. If data is not loaded, this method will wait.

Download several groups of new files in manual sort mode(sortType == .manual), insert them in downloadList at the section which you specify, and return indexes of inserted sections in downloadList immediately. downloadList is a two-dimensional string array: [[String]]. If data is not loaded, this method will wait.

Download a group of new files in manual mode(sortType == .manual), insert them in downloadList at the location which you specify, and return inserted locations in downloadList immediately. If data is not loaded, this method will wait.

Take over outer download task. If data is not loaded, this method will wait.

Resume(continue) tasks and return tasks which are resumed successfully.

This method is not used to download new files, if you want that, use download(_:) series.

A task can be resumed if it satisfies the following conditions:

1. download manager has not reach maxDownloadCount;
2. URL is in downloadList; If task is in toDeleteList and you want to resume it, you must first restore it back to downloadList by restoreToDeletedTasks(_:toLocation:).
3. task can be resumed: its state is not finished and downloading.

Pause downloading tasks and return tasks which are paused successfully. The method has no effect if task is not downloading.

Stop downloading/paused tasks and cancel waitting tasks and return tasks which are stopped successfully.

How to define stop? SDEDownloadManager use NSURLSessionDownloadTask to download files. Usually we pause a task by suspend(), and the task still keeps connection with server; here stop a task by cancel(byProducingResumeData:), disconnect from server.

Delete task records and choose to delete relative files or not, and return a Ditionary includes deleted task’s URL string and its original location in downloadList. If data is not loaded, this method will wait.

PS.: If you want to delete many tasks, you better use deleteTasks(at:keepFinishedFile:deletionHandler:), this method takes more time when delete same tasks.

If isTrashOpened == true, tasks will be moved to toDeleteList.

If you want to do something after a task is deleted in this method, use deleteCompletionHandler. After this method returns, deleteCompletionHandler is reset to nil.

Delete relative files of tasks but keep record, and return locations of tasks whose files are deleted successfully. If data is not loaded, this method will wait.

Specially, if task’s state is .pending, it’s also included in returned result.

If you want to do something after a task is deleted in this method, use deleteCompletionHandler. After this method returns, deleteCompletionHandler is reset to nil.

Redownload file if task’s finished or stopped and return locations of tasks which are restarted successfully. The downloaded file will be deleted before restart.

Resume all unfinished tasks. What’s difference between this method and resumeTasks(_:)? If download manager has reach maxDownloadCount, this method will put task into waitting list, the latter won’t.

Pause all downloading tasks and dequeue waitting tasks in the queue. If pauseDownloadBySuspendingSessionTask == false, this method call stopAllTasks().

Stop all downloading tasks and cancel waitting tasks in the queue.

Delete all task records and choose to delete relative files or not. If data is not loaded, this method will wait.

If you want to do something after a task is deleted in this method, use deleteCompletionHandler. After this method returns, deleteCompletionHandler is reset to nil.

Delete all files but keep records. If data is not loaded, this method will wait.

If you want to do something after a task is deleted in this method, use deleteCompletionHandler. After this method returns, deleteCompletionHandler is reset to nil.

A Boolean value that determines whether download manager should download files over a cellular network.

The default value is false.

The maximum count of task that could download at the same time.

Reducing it will pause redundant downloading tasks automatically; increasing it will resume tasks which are paused in reducing maxDownloadCount.

The defalut value is OperationQueue.defaultMaxConcurrentOperationCount, which means no limit. Assign a nagative or 0 to this property, this property is set to OperationQueue.defaultMaxConcurrentOperationCount directly.

A Boolean value determining that how download manager pause a download task. SDEDownloadManager use NSURLSessionDownloadTask to download file, calling suspend() or cancel(byProducingResumeData:) on NSURLSessionDownloadTask has same results for users: they both pause the download.

If true, call suspend(); if false, call cancel(byProducingResumeData:). The default value is true. This option won’t be saved.

A Boolean value indicating that whether download manager start to download immediately after add a new download task if it has not reach maxDownloadCount. The default value is true. This option won’t be saved.

A Boolean value determining whether move the task to toDeleteList when delete it. If true, task to delete will be moved to the trash first; if false, delete the task directly.

A closure to execute after a task is deleted. Paratmeters in closure:

String: URL string of deleted task.

IndexPath: Deleted task’s location in downloadList or toDeleteList. This parameter should be ignored when only task’s file is deleted in these methods: deleteFilesOfTasks(_:), deleteFilesOfTasks(at:) and deleteFilesOfAllTasks() .

Int: Count of all tasks to delete.

Int: The Nth deleted task. Starts from 1.

A Boolean value determining whether split download list into groups by their alphanumeric order when sorting by file name. This property is used to switch on/off a feature: section index titles. If false, download list won’t be splited into groups. Works only when sortType == .fileName. The default value is false.

A Boolean value determining whether split download list into groups when sorting by add time, like: Today, Yesterday, Last 7 Days, Last 30 Days, Older. If false, download list won’t be splited into groups. Works only when sortType == .addTime. The default value is false.

A Boolean value determining whether split download list into groups when sorting by file size, like: 0 ~ 1 MB, 1 MB ~ 10 MB, 10MB ~ 100 MB, 100 MB ~ 1 GB, Larger Than 1 GB. If false, download list won’t be splited into groups. Works only when sortType == .fileSize. The default value is false.

A Boolean value determining whether display name returned by fileDisplayName(ofTask:) and fileDisplayName(at:) hidden its file extension if it has a file extension. The default vale is true.

This closure provides download activity info. The default value is nil.

beginTrackingDownloadActivity() executes this closure every second in the background until there is no more download or call stopTrackingDownloadActivity() to stop it. If there is no more download activity, downloadCompletionHandler will be executed.

In DownloadListController, this closure is set to update download activity in view.

Dictionary’s key is download URL string, and value is a tuple include task’s download activity info.

• receivedBytes: downloaded bytes for now.

• expectedBytes: file size by bytes. Sometimes it’s negative number, means unknown size.

• speed: downloaded bytes in last second. This value is -1 if download is over, you should remove speed info in your view at this time.

• detailInfo: additional information. Usually it’s nil, unless speed == -1(it means download is over). If this value is not nil, it most be format string of download progress, for example: if task is paused, this value could be 41.6 MB/402.5 MB; if task is finished, this value could be 402.5 MB.

Alternate for downloadActivityHandler in Objective-C code. This closure provides download activity info. The default value is nil.

beginTrackingDownloadActivity() executes this closure every second in the background until there is no more download or call stopTrackingDownloadActivity() to stop it. If there is no more download activity, downloadCompletionHandler will be executed.

This property is Objective-C version of downloadActivityHandler which can’t be seen in Objective-C file.

Dictionary’s key is download URL string, and the value is a dictionary include this task’s download activity info, key and value:

• key: receivedBytes, value type: Int64, downloaded bytes for now.
• key: expectedBytes, value type: Int64, file size by bytes. Sometimes it’s negative number, means unknown size.
• key: speed, value type: Int64, downloaded bytes in last second. This value is -1 if download is over, you should remove speed info in your view at this time.
• key: detailInfo, value type: String, additional information, usually this key-value is not existed, unless speed == -1(it means download is over). Most time it is format string of download progress, for example: if task is paused, this value could be 41.6 MB/402.5 MB; if task is finished, this value could be 402.5 MB.

The closure to execute after all downloads are over. It won’t be executed if stopTrackingDownloadActivity() is called. Specially, if all downloading tasks are paused, this closure will be executed also.

A closure to execute after any task is successful or failed(not include cancelling task and stopping task). The default is nil. If you specify handler for special task in download(_:successOrFailHandler:) or resumeTasks(_:successOrFailHandler:), this closure won’t be executed for the special task.

Closure parameters fileLocation and error, only one is not nil at the same time.

A closure to execute in session delegate method: URLSession:downloadTask:didWriteData:totalBytesWritten:totalBytesExpectedToWrite:. The default value is nil. Although SDEDownloadManager provides download activity track feature, you still could use this closure to implement this target.

A closure to execute in session delegate method: URLSession:downloadTask:didResumeAtOffset:expectedTotalBytes:. The default value is nil.

A closure to execute in session delegate method: URLSessionDidFinishEventsForBackgroundURLSession:. The default value is nil. Use this closure to push a notification after all tasks are done when app is in the background, or update screenshot in Multitasking Screen. Look for configurateListVC() in this project to see the example.

A closure to execute in session delegate method: URLSession:didReceiveChallenge:completionHandler:. The default value is nil. Use this closure to handle session-level authentication.

A closure to execute in session delegate method: URLSession:task:didReceiveChallenge:completionHandler:.

The default value is nil. Use this closure to handle non session-level authentication.

Note: I have handled basic and digest authentication, if authentication type is basic and digest, this closure won’t be executed.

A closure to fetch meta info when download a new file. The default value is nil. Sometimes, meta info fetched by SDEDownloadManager maybe are not what you want, you could append additional info in this closure by updateMetaInfo(_:forTask:). There are two reserved keys for you: TIFileDisplayNameStringKey and TIFileIntroStringKey.

Sort downloadList in place with predefined type or switch sort mode.

Note: This method’s performance is not good when download list has more than 1000 tasks. When parameter sortType is .fileName and indexingFileNameList == true, its performance is worst.

Sort downloadlist in place with powerful predicate.

Object comforms to Sequence has a method sort(by:) to sort list with custom predicate, which is used to implement sortListBy(type:order:), and it also could be used to custom sort in this method, and very powerful, e.g., sortListBy(type: .fileSize, order: .ascending) could be implmented by this method like this:

dm.sortListBy(order: .ascending, taskAscending: {
    dm.fileByteCount(ofTask: $0) < dm.fileByteCount(ofTask: $1)
})

sortListBy(type:order:) supports only four predefined sort types because it can’t use unknown info to sort download list. Now you could add other info for task(by fetchMetaInfoHandler) and sort list by it in this method, e.g., you bulit a list of movies with release year, now sort movies by its release year:

// Just show what this method do, some details are omited.
dm.sortListBy(order: .descending, taskAscending: {
    let year0 = dm.info(ofTask: $0, about: ReleaseYearKey) as! Int
    let year1 = dm.info(ofTask: $1, about: ReleaseYearKey) as! Int
    return year0 < year1
})

In above two examples, there is only one section. When sort list with .fileType, tasks are splited into several sections by their file type. Technically, implement way is: filter tasks that have same trait and integrate these tasks into the same section; then sort sections and tasks in section. It likes sorting a Dictionary. What is appropriate trait? How to sort splited sections, based on what? There is an example, sort a list of songs: splited by its singer and singers are sorted by alphabet, singer’s songs are sorted by release year and song name.

dm.sortListBy(order: .ascending, taskTrait: { URLString in
    // Tasks which return same trait string will be integrated into the same section.
    // Returned trait string is also title for section in `downloadList`.
    // Sections are sorted by trait string in alphabet order.
    // If return nil, task will be in the last section with a placeholder title.
    dm.info(ofTask: URLString, about: SingerKey) as? String
}, taskAscending: {
    // Sort tasks in section.
    let releaseYear0 = dm.info(ofTask: $0, about: ReleaseYearKey) as? Int
    let releaseYear1 = dm.info(ofTask: $1, about: ReleaseYearKey) as? Int
    let sing0 = dm.fileDisplayName(ofTask: $0)!
    let sing1 = dm.fileDisplayName(ofTask: $1)!

    switch (year0, year1){
    case (nil, nil): return sing0 < sing1
    case (nil, _): return true
    case (_, nil): return false
    case (_, _):
        if year0! < year1!{
            return true
        }else if year0! > year1!{
            return false
        }else{
            return sing0 < sing1
        }
    }
})

Above sections are sorted by trait titles in alphabet order, sometimes it’s not what you want, e.g., I want to sort list by add time but split into sections like this:

["Today", "Yesterday", "Last 7 Days", "Last 30 Days", "Older"]

If sort it in in alphabet order, this method will get the following result or reversed:

["Last 30 Days", "Last 7 Days", "Older", "Today", "Yesterday"]

Sectin location can be adjusted manually by moveTasks(inSection:to:), but it’s not good way, and it’s getting worse if some titles are not existed. Actually, it’s easy to fix: add another predicate to reorder trait strings created in taskTrait.

let AddTimeKey = "Key.Date.TaskCreateDate"
let today = Calendar.current.startOfDay(for: Date())
let DayInterval: TimeInterval = 24 * 60 * 60
let traitPriority = ["Today": 0, "Yesterday": -10, "Last 7 Days": -100, "Last 30 Days": -1000, "Older": -10000]

dm.sortListBy(order: .ascending, taskTrait: { URLString in
    // Tasks which have same trait string will be integrated into the same section.
    // Returned trait string is also title for section in `downloadList`.
    // Sections are sorted by trait string with custom predicate `traitAscending`.
    // If return nil, task will be in the last section with a placeholder title.
    let addTime = dm.info(ofTask: URLString, about: AddTimeKey) as! Date
    if Calendar.current.isDateInToday(addTime){
        return "Today"
    }else if Calendar.current.isDateInYesterday(addTime){
        return "Yesterday"
    }else if today.timeIntervalSince(addTime) < 7 * DayInterval{
        return "Last 7 Days"
    }else if today.timeIntervalSince(addTime) < 30 * DayInterval{
        return "Last 30 Days"
    }else{
        return "Older"
    }
}, traitAscending: {
    // Sort trait strings, and relative section is reordered also.
    traitPriority[$0]! < traitPriority[$1]!
}, taskAscending: {
    // Sort tasks in section.
    dm.fileDisplayName(ofTask: $0)! < dm.fileDisplayName(ofTask: $1)!
})

Note: sortType will be set to .manual in this method. I was going to add another sort mode .custom, but there is no benefit except adding complexity.

Move task’s location in downloadList. It’s your responsibility to check indexPath’s validity.

Move a whole section in downloadList. It’s your responsibility to check section’s validity.

If any download task is executing, download manager begins to collect download activity info, include: download size for now, file size, download speed, optional additional information, and then execute downloadActivityHandler closure every second until no more download.

You should update UI in downloadActivityHandler closure. DownloadListController class is a good choice, I have done everything for you.

Stop both collecting download activity info and executing downloadActivityHandler closure immediately. You should call this method to reduce resource consumption after your view disappear; call beginTrackingDownloadActivity() to continue after your view appear again. downloadCompletionHandler closure won’t be executed if call this method.

Request a thumbnail with specified height. This method is synchronous.

If file is not image or video, and you don’t custom thumbnail for it by setCustomThumbnail(_:forTask:), this method returns a type icon. About type icon, you could offer custom icon(must be png file) for specified type by naming image file with file extension’s uppercased, e.g., you want a .psd file to display custom icon, add PSD.png to this library, into /Resource/FileExtensionIcon.xcassets, this method will return an UIImage object inited from PSD.png for all .psd files.

Remove all thumbnails.

Custom thumbnail for the task, except for image file.

Remove custom thumbnail for the task and return it.

Clean up to-delete tasks in toDeleteList and return a Dictionary includes deleted task’s URL string and its location info.

Clean up all to-delete tasks in toDeleteList and return a Dictionary includes deleted task’s URL string and its location info..

Restore to-delete tasks in toDeleteList back to downloadList and return locations of restored deleted tasks in toDeleteList.

Restore all to-delete tasks in toDeleteList back to downloadList and return locations of restored deleted tasks in toDeleteList.

The hash value.

==

Reserved key for outer to store file name in meta info. More details in SDEDownloadManager‘s fetchMetaInfoHandler.

Reserved key for outer to store file intro in meta info. More details in SDEDownloadManager‘s fetchMetaInfoHandler.

Update or add meta info for download task.

The notification is posted for any interrupted download task in download manager when app is forcely quited and relanched again. Task’s download info is changed, which can be get from downloadDetail(ofTask:).

Get the only value in notification info, task URL string: notification.userInfo?["URLString"] as? String.

The notification is posted for task which changed display name. Task’s display name can be get from fileDisplayName(ofTask:).

Get the only value in notification info, task URL string: notification.userInfo?["URLString"] as? String.

The notification is posted for task whose file is downloaded before download manager begin to track. Task’s download info is changed, which can be get from downloadDetail(ofTask:).

Get the only value in notification info, task URL string: notification.userInfo?["URLString"] as? String.

The notification is posted for task whose downloaded temporary file is processing. Task’s download info is changed, which can be get from downloadDetail(ofTask:).

Get the only value in notification info, task URL string: notification.userInfo?["URLString"] as? String.

The notification is posted for task whose downloaded temporary file has been processed. Task’s download info is changed, which can be get from downloadDetail(ofTask:).

Get the only value in notification info, task URL string: notification.userInfo?["URLString"] as? String.

Get the location of download task in downloadList based on its download URL string.

Get the URL string of download task based on its location in downloadList.

Resume(continue) tasks at specified locations and return locations of tasks which are resumed successfully.

Pause tasks at specified locations and return locations of tasks which are paused successfully.

If pauseDownloadBySuspendingSessionTask == true, it suspends the relative NSURLSessionDownloadTask object; otherwise, stop it by ‘cancel(byProducingResumeData:)’, they are same results for users.

Stop tasks at specified locations and return locations of tasks which are stopped successfully.

Delete tasks at specified locations and return a Dictionary includes deleted task’s URL string and its original location in downloadList. If data is not loaded, this method will wait.

If isTrashOpened == true, tasks will be moved to toDeleteList.

If you want to do something after a task is deleted in this method, use deleteCompletionHandler. After this method returns, deleteCompletionHandler is reset to nil.

Delete file only and keep task record, and return locations of tasks whose file are deleted successfully. If data is not loaded, this method will wait.

Relative file will be deleted no matter whether file is downloaded completely or not.

Specially, if task’s state is .pending, it’s also included in returned result.

If you want to do something after a task is deleted in this method, use deleteCompletionHandler. After this method returns, deleteCompletionHandler is reset to nil.

Redownload files of tasks at the specified locations if task is finished or stopped, and return locations of tasks which are restarted successfully. The downloaded file will be deleted before restart.

Resume(continue) tasks in specified section and return locations of tasks which are resumed successfully.

Pause tasks in specified section and return locations of tasks which are paused successfully.

If pauseDownloadBySuspendingSessionTask == true, it suspends the relative NSURLSessionDownloadTask object; otherwise, stop it by ‘cancel(byProducingResumeData:)’, they are same results for users.

Stop tasks in specified section and return locations of tasks which are stopped successfully.

Delete tasks in specified section and return a Dictionary includes deleted task’s URL string and its original location in downloadList. If data is not loaded, this method will wait.

If isTrashOpened == true, tasks will be moved to toDeleteList.

If you want to do something after a task is deleted in this method, use deleteCompletionHandler. After this method returns, deleteCompletionHandler is reset to nil.

Delete file only and keep task record, and return locations of tasks whose file are deleted successfully. If data is not loaded, this method will wait.

Relative file will be deleted no matter whether file is downloaded completely or not.

If you want to do something after a task is deleted in this method, use deleteCompletionHandler. After this method returns, deleteCompletionHandler is reset to nil.

Redownload files of tasks in specified section if task is finished or stopped, and return locations of tasks which are restarted successfully. The downloaded file will be deleted before restart.

Clean up to-delete tasks in toDeleteList at specified locations, and return a Dictionary includes deleted task’s URL string and its location info.

If you want to do something after a task is deleted in this method, use deleteCompletionHandler. After this method returns, deleteCompletionHandler is reset to nil.

Clean up to-delete tasks in toDeleteList in specified continuous range, and return a Dictionary includes deleted task’s URL string and its location info..

If you want to do something after a task is deleted in this method, use deleteCompletionHandler. After this method returns, deleteCompletionHandler is reset to nil.

Restore to-delete tasks in toDeleteList at specified locations back to downloadList and return original locations of restored tasks in toDeleteList.

Change file display name.

Change section title in manual mode.

Query download task’s location in downloadList.

Query info of download task.

Query specified info about download task. This method is designed to query info which is added from outer by fetchMetaInfoHandler.

Query download task state.

Query the display name of file in the download task. If hiddenFileExtension == true, returned string doesn’t include file extension.

Query download progress([0, 1]). If task is downloading, value returned by this method is not right. How to get realtime progress when downloading? The answer is property downloadActivityHandler.

Query file size by byte count.

Query local path of downloaded file.

Query local path of downloaded file by URL.

Query detail about download activity.

Sometimes it’s error info. And most times this method return task’s download progress info: if task is not finished, return a string of (downloadedSize)/(fileSize); if finished, return a string of (fileSize).

Note: This method returns nil if task is downloading, you can fetch it in downloadActivityHandler.

Query file type. Predefined types: Image, Audio, Video, Document, Other.

Check whether downloaded file is existed.

Query the URL string of download task at specified location.

Query download task state.

Query display name of file in the download task. If hiddenFileExtension == true, returned string doesn’t include file extension.

Query download progress([0, 1]). If task is downloading, value returned by this method is not right. How to get realtime progress when downloading? The answer is property downloadActivityHandler.

Query file size by byte count.

Query downloaded file’s absolute path.

Query downloaded file’s absolute path by URL.

Query detail about download activity.

Sometimes it’s error info. And most times this method return task’s download progress info: if task is not finished, return a string of (downloadedSize)/(fileSize); if finished, return a string of (fileSize).

Note: This method returns nil if task is downloading, you can fetch it in downloadActivityHandler.

Query file type. Predefined types: Image, Audio, Video, Document, Other.

Debug method to reproduce download data with random create date and file size. If the count of existed tasks is larger than specified count, this method will reduce it to target count.

Print task info. You should custom code to print info you want.