WebDAV-Swift

WebDAV communication library for Swift

Table of contents

• Install
• Usage
  • Account
  • Making requests
  • Listing files
  • Data cache
  • Images
  • Thumbnails
  • Theming
• Upgrading
• Contribution
  • Adding a WebDAV account

Install

Install using Swift Package Manager.

https://github.com/Isvvc/WebDAV-Swift.git

In Xcode: File -> Swift Packages -> Add Package Dependency...
or add in Project settings.

Usage

import WebDAV

Create and instance of the WebDAV class. This currently has two functions: listFiles and upload. WebDAV functions require a path, account, and password.

Account

WebDAVAccount is a protocol that contains a username and base URL for the WebDAV server. These properties are optional for easier conformance, but they must not be optional when making a request, or the request will fail.

Create a class or struct that conforms to WebDAVAccount that can be used in WebDAV calls, or use the provided SimpleAccount struct. Because the properties are optional, conformance can be added to CoreData entities.

When instantiating a WebDAVAccount, the baseURL property should be the URL to access the WebDAV server. For Nextcloud, this should include remote.php/dav/files/[username]/ (can be found under Settings in the bottom-left of any Files page).

Example:

SimpleAccount(username: "test", baseURL: "https://nextcloud.example.com/remote.php/dav/files/test/")

Making requests

Every request requires a path, WebDAVAccount, and password. There is no "logging in". This is so apps can easily support having multiple accounts without having to log in or out of each.

Passwords

It is highly recommended you use an app-specific password (for Nextcloud, see Login flow v2). Do not store the user's password in plain text. Use URLCredentialStorage or Keychain (or something like KeychainSwift for easier use).

Path

The path passed into functions should be the path to the file or directory relative to the baseURL in your account.

For functions that read from or write to a file, this path should include the file name and extension.

Functions

The basic WebDAV functions currently available include

• listFiles
• upload
• download
• createFolder
• deleteFile
• moveFile
• copyFile

These functions will each return a URLSessionTask which can be cancelled later.

Example

let baseURL = "https://nextcloud.example.com/remote.php/dav/files/Username/"
let account = SimpleAccount(username: username, baseURL: baseURL)
let path = "file.txt"
let data = "File contents".data(using: .utf8)
        
webDAV.upload(data: data, toPath: path, account: account, password: password) { error in
    // Check the error
}

Listing files

The listFiles function, if successful, will complete with a WebDAVFile array, which will be cached to memory and disk for quick retrieval later. By default, subsequent calls of listFiles on the same path with the same account will give the cached results instead of making a network request. See Caching behavior for how to change this behavior.

A useful option for listing files in particular is .requestEvenIfCached:

webDAV.listFiles(atPath: path, account: account, password: password, caching: .requestEvenIfCached) { files, error in
    // Show the cached files immediately.
    // Update to show the newly fetched files list after the request is complete.
}

In this case, if there are cached files, the completion closure will run immediately with those cached files. Then a network request will be made to get an updated files list. If the files list from the server is unchanged from the cache, the function ends here and nothing else is called. If the files list from the server is different from the cache, the completion closure will run a second time with the new files list.

The files cache can be cleared using clearFilesCache, clearFilesDiskCache, or clearFilesMemoryCache.

Data cache

Included is functionality for downloading and caching data, images, and thumbnails (on Nextcloud servers).

Data downloaded using the download function, or the various image and thumbnail fetching functions, will cache to both memory and disk. The memory function is based off of NSCache, meaning it uses Apple's own auto-eviction policies to clear up system memory. The disk cache data is stored in the app.lyons.webdav-swift folder in the caches directory.

Data cache functions include

• getCachedData
• deleteCachedData
• deleteAllCachedData
• getCacheByteCount
• getCacheSize
• cachedDataURL
• cachedDataURLIfExists
• deleteAllDiskCachedData

Caching behavior

Default caching behavior is to return a cached result instead of making a request if there is one. Otherwise, make a request and cache the result.

Use the caching options parameter in functions to change the caching behavior based on WebDAVCachingOptions. Setting the caching options to an empty set will use default behavior.

Caching options include

• doNotCacheResult
• doNotReturnCachedResult
• removeExistingCache
  • Removes the cached result after returning it, if it exists.
  • Use with doNotReturnCachedResult if you do not want the cached result returned.
• requestEvenIfCached
  • The completion closure for the request will run once with the cached data, then again with the newly fetched data, assuming it is different.

Convenience options include

• ignoreCache will ignore the cached result if there is one, and won't cache the new result.
  • Same as [.doNotCacheResult, .doNotReturnCachedResult].
• disableCache disables all caching for the request and deletes any existing cache for it.
  • Same as [.doNotCacheResult, .removeExistingCache, .doNotReturnCachedResult].

Images

Images can be downloaded and cached using downloadImage. This will complete with a UIImage if available and caches the same way as the data cache.

Image functions include:

• downloadImage
• getCachedImage

Why is there no deleteCachedImage or cachedImageURL function when there is getCachedThumbnail and cachedThumbnailURL?
Images are stored in the disk cache the same way as data. The image-specific functions exist as a convenience for converting the data to UIImages and caching them in memory that way. Since the cached data URL does not change whether the data is an image or not, deleteCachedData and cachedDataURL can be used for images.

Thumbnail preview

If there are already cached thumbnails for the image you are trying to fetch, you can use the preview parameter to specify that you would like to get that thumbnail first while the full-size image is downloading. When you do this, the completion closure will run with a .placeholder error on the call with the thumbnail.

webDAV.downloadImage(path: imagePath, account: account, password: password, preview: .memoryOnly) { image, error in
    switch error {
    case .none, .placeholder:
        // .none is the full-size image.
        // .placeholder is the thumbnail.
        // The completion closure will not be run with the thumbnail after
        // it is run with the full-size image, so assuming you don't have
        // a use for the thumbnail after the full-size image loads, you
        // shouldn't need to check which it is before displaying.
        break
    case .some(let unexpectedError):
        // Log the error
    }
    
    // Display the image
}

See Thumbnails for more details on thumbnails.

Thumbnails

Along with downloading full-sized images, you can download thumbnails from Nextcloud servers. This currently only works with Nextcloud servers as thumbnail generation is not part of the WebDAV standard.

Thumbnail generation requires you to specify the properties for how the server should render the thumbnail. These properties exist as ThumbnailProperties objects and include dimensions and content mode. If no dimensions are specified, the server's default will be used (default is 64x64 on Nextcloud). When getting the URL of or deleting a cached URL, you must also specify these properties in order to access the correct specific thumbnail. If you wish to access all thumbnails for a specific image at once, you can use getAllCachedThumbnails and deleteAllCachedThumbnails.

Example:

webDAV.downloadThumbnail(path: imagePath, account: account, password: password, with: .init((width: 512, height: 512), contentMode: .fill)) { image, error in
    // Check the error
    // Display the image
}

Note that ThumbnailProperties objects can also be initialized using a CGSize, but doing so will truncate the size to integer pixel counts.

Thumbnail functions include

• downloadThumbnail
• getCachedThumbnail
• getAllCachedThumbnails
• deleteCachedThumbnail
• deleteAllCachedThumbnails
• cachedThumbnailURL
• cachedThumbnailURLIfExists

Theming

WebDAV servers that support OCS (such as Nextcloud and ownCloud) can give you theming information including accent color, name, slogan, background image, etc. Two functions exist for this:

• getNextcloudColorHex
• getNextcloudTheme

getNextcloudColorHex will give the server's accent color as a hex code starting with '#' (eg #0082c9). getNextcloudTheme will give the server's full theming information in the form of an OCSTheme object.

Upgrading

Version 2.x used 3lvis/Networking for its image caching, but this was replaced with a custom in-house caching solution in 3.0. If upgrading from v2 to v3, run the function clearV2Cache() in order to remove previously cached data.

For example, you could run something like this on startup

if !UserDefaults.standard.bool(forKey: "webDAV-v3-upgrade") {
    try? webDAV.clearV2Cache()
    UserDefaults.standard.setValue(true, forKey: "webDAV-v3-upgrade")
}

Contribution

This package depends on drmohundro/SWXMLHash which should automatically be fetched by Swift Package Manager in Xcode.

To test any contributions you make, make test functions in WebDAVTests. In order to run tests, you need to add a WebDAV account to the environment variables as described below.

Adding a WebDAV account

You'll need to add a WebDAV account to your scheme to be able to test.

Edit your scheme in Xcode. Ensure the "Shared" checkbox is unchecked to keep the scheme private.

Under Arguments in Test, add the following environment variables:

• webdav_user: The username for your WebDAV account to test with
• webdav_password: The password for your WebDAV account
• webdav_url: The URL of the WebDAV server your account is on
• image_path: The path to an image file of type jpg/jpeg, png, or gif in the WebDAV storage

Note that running the tests will create files on your WebDAV server, though they should also be deleted, assuming all the tests pass.