HTTP file system

This file system provides a read-only implementation for a file system based on the HTTP protocol. It does not browse the server directory listing itself - instead, each directory must contain a .dirls file describing its content, in the format:

D/F   Length   Created    Modified    Hash Algorithm    Hash    Name

This file is generated by the TagBites.IO.Http.HttpFileSystem.CreateDirectoryInfo method, which walks a directory (recursively, by default) and writes a .dirls file into it and every subdirectory:

// Publish an existing directory (e.g. before uploading it to a web server)
HttpFileSystem.CreateDirectoryInfo(FileSystem.Local.GetDirectory("wwwroot/files"));

Alternatively, CreateRecursiveDirectoryInfo writes a single .dirrls file at the root containing entries for the whole directory tree. It is picked up automatically for a recursive listing of the root directory, avoiding one HTTP request per subdirectory:

HttpFileSystem.CreateRecursiveDirectoryInfo(FileSystem.Local.GetDirectory("wwwroot/files"), ignoredPaths: new[] { "temp" });

Usage

FileSystem fileSystem = TagBites.IO.Http.HttpFileSystem.Create("address");
// ... using like standard file system

Additional options - custom .dirls file name, text encoding and request timeout - can be passed with HttpFileSystemOptions:

FileSystem fileSystem = TagBites.IO.Http.HttpFileSystem.Create("address", new HttpFileSystemOptions
{
    DirectoryInfoFileName = ".dirls",
    Timeout = 10000,
    PreventCache = true
});

Publishing through another file system

Because the HTTP file system itself is read-only, content is typically published through another writable file system (e.g. FTP) that uploads to the same address the HTTP file system later reads from. CreateBuilder wraps such a file system so every write automatically (re)creates the .dirls file for the affected directory, keeping it in sync without calling CreateDirectoryInfo by hand:

var ftpFileSystem = TagBites.IO.Ftp.FtpFileSystem.Create(address, username, password);
FileSystem publishFileSystem = TagBites.IO.Http.HttpFileSystem.CreateBuilder(ftpFileSystem);

// writes go to FTP and keep .dirls files up to date
await publishFileSystem.GetFile("file.txt").WriteAllTextAsync("content");

// reads later happen through plain HTTP
FileSystem fileSystem = TagBites.IO.Http.HttpFileSystem.Create(address);

Full implementation on github: TagBites.IO.Http.