# Development post-it notes.Things/Snippets of code I should not forget.Made as a quick cheatsheet for me and contributors to check if they're in doubt.## Using context to retrieve important values.Certain middlewares will store a couple of values on the context to make your developer life easier. Here's a couple examples:```gouser, ok := r.Context().Value(lib.UserKey).(*types.User)session, ok := r.Context().Value(lib.SessionKey).(string)loggedIn, ok := r.Context().Value(lib.LoggedInKey).(bool) // this should be fine to be used anywhere.repo, ok := r.Context().Value(md.RepoKey).(types.Repo) // provided by the repo middleware```**IMPORTANT** *AND* **TODO**: use `val, ok := ctx.Value(key).(Type); if !ok { ... }` to check if the value is set.## Form validation.Use the md.ValidateForm such as```gotype LoginForm struct {	Email    string `form:"email"    validate:"required,email"`	Password string `form:"password" validate:"required,min=8"`}md.ValidateForm[LoginForm](http.HandlerFunc(a.login)) // Use handle, not handleFunc.```and retrieve the form using ```goform, ok := md.Form[LoginForm](r) // r being the request```Bear in mind forms have that special property because of `contextKey`.Forms are CSRF-protected. `{{ .csrfField }}` must be added inside each form.## Mux routing.I use `gorilla/mux` as a router:- Use a blank space `""` for indexes.- Use `{path:.+}` for those recursive paths.- Define all routers in app.go since it's be easier to manage.## Rendering templates.Use the following code:```goa.Render(w, r, "base", "repo/view", map[string]any{"Repo": repo})```Where `a` is your *App, `base` the layout, `repo/view` is the template, and `map[string]any{"Repo": repo}` is the data, accessible as `.Repo`Use `{{.sshDomain}}` and `{{.sshPort}}` to get the domain and port the SSH server will be listening at.Useful variables:```go{{.loggedIn}} //  bool, is user logged in? self-explanatory.{{.user}} // types.User (if loggedIn is true){{.sshDomain}} // domain of the SSH server.{{.sshPort}} // port which the SSH server is listening from.```When you need to access the root "." while (e.g) ranging, use "$" to access it. Example:```go{{range .Files}}    {{$.DirectoryName}}/{{.Name}}{{end}}``` ### Template rendering utils.I made a couple utils to be used on the templates.For instance:```go{{if IsText .Blob.Type}}    <pre><code>{{.Blob.Content}}</code></pre>{{else if IsImage .Blob.Mime}}    <img src="{{Src .Blob.Content .Blob.Mime}}">{{end}}```ALWAYS USE `{{RepoRoot .Meta}}` instead of "/~(user)/(repo-name)/". It's easier to change later.It has a leading slash and no trailing slash.```go{{RepoRoot .DBRepo}} -> "/~poyo/banana"{{TruncateStr "hello world" 5}} // -> "hello"{{Mime .Blob}} // -> "image/png"```You can check the full list at the templating function itself.### Time.When rendering a date, pass in a UTC date into any element with a class `local-time`, and `time.js` will convert it to the user's local time.Example:```html<time class="local-time" datetime="{{.CreatedAt}}">{{.CreatedAt}}</time>```### CSS Styling:`.inline` for inlined and gapped containers.## Message and Error displaying.`?msg=AuthSuccess` and `?err=RequireAuth` are examples of query params that will show a banner on the page.Keep in mind, validation errors are Base64 encoded (urlencoded) and are passed as `?err=ValidationErr-(base64)`. The messages and validation middleware handle it, so don't worry about it much.CSS for errors and messages is on the main stylesheet (`styles.css`).`.message`, `.warning` and `.error` have a slight vertical margin. If you use the same class names as HTML attributes, they will have no margin. ## Lib/Submodules.Please, separate stuff into lib submodules to avoid circular imports.I had to suffer an hour of debugging because I implemented git handling on a db function. I scrapped everything and rewrote it separately, and it worked. That's proof separating is better!## Hackatime.Users can login using Hack Club's Hackatime. Why? To get stats on their projects.## Git.When opening a repo with `git.Repo()`, make sure to add `defer repo.Close()` after it.## Resources - [https://github.com/firecracker-microvm/firecracker/blob/main/docs/prod-host-setup.md](Firecracker production guide)