Status: {{ .Rocket.Status }}
{{ end }} ``` ### Rendering Pages Copper provides `chttp.HTMLReaderWriter` for writing HTML responses. Inject it into your router and call `WriteHTML`: ```go theme={null} type NewRouterParams struct { Rockets *Svc HTML *chttp.HTMLReaderWriter Logger clogger.Logger } ``` ```go theme={null} func (ro *Router) HandleRocketPage(w http.ResponseWriter, r *http.Request) { rocket, err := ro.rockets.Get(r.Context(), chttp.URLParams(r)["id"]) if err != nil { ro.html.WriteHTMLError(w, r, err) return } ro.html.WriteHTML(w, r, chttp.WriteHTMLParams{ PageTemplate: "rocket.html", Data: map[string]any{"Rocket": rocket}, }) } ``` `LayoutTemplate` defaults to `main.html` and `StatusCode` to `200`; you may set either explicitly when needed. On errors, an appropriate page will automatically be chosen for you: `internal-error.html` for 500s and `not-found.html` for 404s. ### Template Functions Every template has the full [Sprig](https://masterminds.github.io/sprig/) function library available, including `upper`, `date`, and `mustToRawJson`. You may add your own functions using `chttp.HTMLRenderFunc`. Since render funcs receive the current request, they can expose per-request state such as the signed-in user: ```go web/wire.go theme={null} func HTMLRenderFuncs() []chttp.HTMLRenderFunc { return []chttp.HTMLRenderFunc{ { Name: "currentUser", Func: func(r *http.Request) (any, error) { return func() *sessions.User { return sessions.UserFromCtx(r.Context()) }, nil }, }, } } ``` ```html theme={null}Welcome back, {{ (currentUser).Name }}
``` ### Partials Partials in `web/src/partials` are reusable fragments. Render one inside any template with the built-in `partial` function: ```html theme={null} {{ range .Rockets }} {{ partial "rocket-card" . }} {{ end }} ``` You may also write a partial directly as a response, which works well for [HTMX](https://htmx.org)-style updates that swap a fragment into the page: ```go theme={null} func (ro *Router) HandleRocketStatus(w http.ResponseWriter, r *http.Request) { rocket, err := ro.rockets.Get(r.Context(), chttp.URLParams(r)["id"]) if err != nil { ro.html.WriteHTMLError(w, r, err) return } ro.html.WritePartial(w, r, chttp.WritePartialParams{ Name: "rocket-card", Data: rocket, }) } ``` ### Static Assets Files in `web/public` are served under `/static/`. For example, `web/public/logo.svg` is available at `/static/logo.svg`. In production these files are embedded into your binary, while in development they are read from disk. ### Local Development Two config flags make template development pleasant, and both are enabled in `config/dev.toml` for new projects: ```toml theme={null} [chttp] use_local_html = true # read templates & static files live from ./web — no rebuild render_html_error = true # show the actual error in the browser instead of a blank 500 ``` ### Single-Page Apps If your frontend handles its own routing, you may configure every unmatched GET request to render `index.html`: ```toml theme={null} [chttp] enable_single_page_routing = true ``` ### API-Only Apps If your application doesn't serve HTML at all, use `chttp.WireModuleEmptyHTML` in place of the HTML and static dir bindings; it satisfies wire with empty stand-ins. Projects created with `-frontend=none` are configured this way.