I would like to Execute a different template based on a http error code.
I was thinking to use template.ParseFiles(), but I am confused how to do this dynamically. In fact, ParseFiles() can load an array of strings (filenames).
Do I have to ParseFiles() for every file individually, in order to assign its result to an error code in a map? If I ParseFiles() all into an array, how can I then assign each of the templates to the error code?
I would like to avoid having to ParseFiles() on each request, I would prefer to do the parsing in init() and Execute only on request.
Here's what I have so far (does not compile yet):
package main
import (
"os"
"html/template"
"net/http"
)
var templateMap map[int]*template.Template
func init() {
initErrHandling()
}
func initErrHandling() {
templateMap = make(map[int]*template.Template)
templateMap[0] = "generic.html" //default
templateMap[400] = "generic.html"
templateMap[401] = "unauthorized.html"
templateMap[403] = "forbidden.html"
templateMap[404] = "notfound.html"
templateMap[422] = "invalidparams.html"
templateMap[500] = "generic.html"
template.ParseFiles() //parseFiles all files in one call, or parseFiles one by one and assign to error code, e.g. templateMap[404],_ = template.parseFiles("notfound.html")?
}
func getTemplate(code int) (*template.Template) {
if val, tmpl := templateMap[code]; tmpl {
return tmpl
} else {
return templateMap[0]
}
}
func showError(w http.ResponseWriter, code int) {
getTemplate(code).Execute(w)
}
func main() {
showError(os.Stdout, 400)
}
Use one map to record the file names and a second map for the parsed templates:
func initErrHandling() { // call from init()
fnames := map[int]string{
0: "generic.html", //default
400: "generic.html",
401: "unauthorized.html",
403: "forbidden.html",
404: "notfound.html",
422: "invalidparams.html",
500: "generic.html",
}
templateMap = make(map[int]*template.Template)
for code, fname := range fnames {
templateMap[code] = template.Must(template.ParseFiles(fname))
}
}