Ratchet

An example web application in Golang.

https://lets-go.alexedwards.net/sample/02.09-serving-static-files.html

Project Structure

Loosely inspired by the organization of WTFDial,

• Application domain types reside in the project root (User, UserService, etc)
• Implementations of the application domain reside in the subpackages sqlite, http, etc.
• Everything is tied together in the cmd subpackages

Application Domain

This is project is an Indie reader inspired by Feedi.

Implementation Subpackages

The subpackages function as an adapter between our domain and the technology used to implement the domain. For example sqlite.FeedService implements the ratchet.FeedService using SQLite.

Subpackages ideally SHOULD NOT know about one another and SHOULD communicate in terms of the application domain.

A special mock packages can be used to create simple mocks for each application domain interface. This will allow each subpackages unit tests to share a common set of mocks so layers can be tested in isolatation.

Binary Packages

With loosely coupledc subpackages the application is wired together in the cmd subpackages to produce a final binary.

The cmd packages are ultimately the interface between the application domain and the operator. Configuration of types and any CLI flags SHOULD live in these packages.

Development

You can build ratchet locally by cloning the respository, then run

make go install ./cmd/...

The ratchetd cmd binary uses Oauth so you will need to create a new Oauth App. The vlaue of the authorization callback must be the hostname and IP at which clients can access the ratchetd server.

Additional Resources

• Content Range Requests
• HTTP 204 and 205 Status Codes
• How to Disable FileServer Directory Listings
• Understand Mutexs in Go
• Structured Logging in Go with log/slog
• Exit Codes with special meaning
• Organizing Database Access in Go

Go http.FileServer

Supports If-Modified-Since and Last-Modified headers

curl -i -H "If-Modified-Since: 
Thu, 04 May 2017 13:07:52 GMT" http://localhost:5001/static/img/logo.png
HTTP/1.1 304 Not Modified
Last-Modified: Thu, 04 May 2017 13:07:52 GMT
Date: Sun, 12 Jan 2025 14:26:06 GMT

Supports Range Requests and 206 Partial Content responses.

curl -i -H "Range: bytes=100-199" --output - http://localhost:5001/static/img/logo.png
HTTP/1.1 206 Partial Content
Accept-Ranges: bytes
Content-Length: 100
Content-Range: bytes 100-199/1075
Content-Type: image/png
Last-Modified: Thu, 04 May 2017 13:07:52 GMT
Date: Sun, 12 Jan 2025 14:18:32 GMT

• The Content-Type is automatically set from the file extension using the mime.TypeByExtension() function. You can add your own custom extensions and content types using the mime.AddExtensionType() function if necessary.

• Sometimes you might want to serve a single file from within a handler. For this there’s the http.ServeFile() function, which you can use like so:

func downloadHandler(w http.ResponseWriter, r *http.Request) {
    http.ServeFile(w, r, "./ui/static/file.zip")
}

Warning: http.ServeFile() does not automatically sanitize the file path. If you’re constructing a file path from untrusted user input, to avoid directory traversal attacks you must sanitize the input with filepath.Clean() before using it.