README
¶
eHTML
Package ehtml provides ways of rendering an error html page, using Go templates.
Too many time we've found ourselves writing customized error pages. With this package we hope to relieve ourselves from this trivial, but yet repetetive job.
Simply load your templates into the object and call Render() with the request, status code and optional data.
Writing a generic web server? Waiting for templates from your designer? No problem! A default placeholder template will be used instead.
Example
Define some templates:
{{- define "head" -}}
<head>
<meta charset="utf-8">
<title>{{ .String }}</title>
</head>
{{- end -}}
{{- define "error" -}}
<!DOCTYPE html>
<html lang="en">
{{ template "head" . }}
<body>
<h1>{{ .Status.Int }} {{ .Status }}</h1>
<p>
{{ .Message }} while serving {{ .Request.URL.Path }}.
Request ID: {{ .ReqID }}
</p>
<p><i>This is a generic error page</i><p>
</body>
</html>
{{- end -}}
{{- define "500" -}}
<!DOCTYPE html>
<html lang="en">
{{ template "head" . }}
<body>
<h1>Snap!</h1>
<h2>{{ .Status.Int }} {{ .Status }}</h2>
<p>
Something went really wrong and we've been notified!
Please try again later.
</p>
<p><i>
Error: {{ .Message }} while serving {{ .Request.URL.Path }}.
Request ID: {{ .ReqID }}
</i></p>
</body>
</html>
{{- end -}}
{{- define "404" -}}
<!DOCTYPE html>
<html lang="en">
<head>
{{ template "head" . }}
</head>
<body>
<h1>{{ .Status.Int}} {{ .Status }}</h1>
<p>
{{ .Request.URL.Path }} could not be found.
</p>
</body>
</html>
{{- end -}}
Parse them into a globale variable (or part of your Handler object). One can also use ParseFiles() or ParseGlob():
var errorPages = &Pages{template.Must(template.New("error").Parse(templates))}
If you are using Gorilla mux, set the NotFoundHandler
rtr := mux.NewRouter()
rtr.NotFoundHandler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if err := p.Render(w, &Data{Req: r, Code: http.StatusNotFound}); err != nil {
log.Println(err)
}
})
Optionally, extend Data to add more context.
As an alternative, you can also roll your own implementation of Provider.
type data struct {
Data
ReqID int
}
And whenever something goes wrong in your handlers, call Render():
err := p.Render(w, &data{Data{req, http.StatusInternalServerError, "DB connection"}, 666})
if err != nil {
log.Println(err)
}
License
BSD 3 Clause.
Documentation
¶
Overview ¶
Package ehtml provides ways of rendering an error html page, using Go templates. It supports status code specific templates, with fallback to a generic error template. If no templates are defined, it uses a simple placeholder template.
Define some templates:
{{- define "head" -}}
<head>
<meta charset="utf-8">
<title>{{ .String }}</title>
</head>
{{- end -}}
{{- define "error" -}}
<!DOCTYPE html>
<html lang="en">
{{ template "head" . }}
<body>
<h1>{{ .Status.Int }} {{ .Status }}</h1>
<p>
{{ .Message }} while serving {{ .Request.URL.Path }}.
Request ID: {{ .ReqID }}
</p>
<p><i>This is a generic error page</i><p>
</body>
</html>
{{- end -}}
{{- define "500" -}}
<!DOCTYPE html>
<html lang="en">
{{ template "head" . }}
<body>
<h1>Snap!</h1>
<h2>{{ .Status.Int }} {{ .Status }}</h2>
<p>
Something went really wrong and we've been notified!
Please try again later.
</p>
<p><i>
Error: {{ .Message }} while serving {{ .Request.URL.Path }}.
Request ID: {{ .ReqID }}
</i></p>
</body>
</html>
{{- end -}}
{{- define "404" -}}
<!DOCTYPE html>
<html lang="en">
<head>
{{ template "head" . }}
</head>
<body>
<h1>{{ .Status.Int}} {{ .Status }}</h1>
<p>
{{ .Request.URL.Path }} could not be found.
</p>
</body>
</html>
{{- end -}}
Parse them into a globale variable (or part of your Handler object):
var errorPages = &Pages{template.Must(template.New("error").Parse(templates))}
If you are using Gorilla mux, set the `NotFoundHandler`
rtr := mux.NewRouter()
rtr.NotFoundHandler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if err := p.Render(w, &Data{Req: r, Code: http.StatusNotFound}); err != nil {
log.Println(err)
}
})
Optionally, extend `Data` to add more context. As an alternative, you can also roll your own implementation of `Provider`.
type data struct {
Data
ReqID int
}
And whenever something goes wrong in your handlers, call `Render()`:
err := p.Render(w, &data{Data{req, http.StatusInternalServerError, "DB connection"}, 666})
if err != nil {
log.Println(err)
}
Example ¶
p := &Pages{template.Must(template.New("error").Parse(exampleTemplates))}
req := httptest.NewRequest("GET", "http://example.com/foo", nil)
w := httptest.NewRecorder()
// Extend Data, as needed
type data struct {
Data
ReqID int
}
// Serves the client with the "500" template
err := p.Render(w, &data{Data{req, http.StatusInternalServerError, "DB connection"}, 666})
if err != nil {
log.Println(err)
}
resp := w.Result()
body, _ := ioutil.ReadAll(resp.Body)
fmt.Println(resp.StatusCode)
fmt.Println(string(body))
w = httptest.NewRecorder()
// 400 is not defined, so the generic "error" template is used instead.
err = p.Render(w, &data{Data{req, http.StatusBadRequest, "Missing token in URL"}, 667})
if err != nil {
log.Println(err)
}
resp = w.Result()
body, _ = ioutil.ReadAll(resp.Body)
fmt.Println(resp.StatusCode)
fmt.Println(string(body))
Example (NotFoundHandler) ¶
p := &Pages{template.Must(template.New("error").Parse(exampleTemplates))}
rtr := mux.NewRouter()
rtr.NotFoundHandler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if err := p.Render(w, &Data{Req: r, Code: http.StatusNotFound}); err != nil {
log.Println(err)
}
})
Index ¶
Examples ¶
Constants ¶
const DefaultTmpl = `` /* 224-byte string literal not displayed */
DefaultTmpl is a placeholder template for `Pages.Render()`
const RenderError = "500 Internal server error. While handling:\n%s"
RenderError is returned to the client if the template failed to render. This doesn't look nice, but it prevents partial responses.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Pages ¶
Pages allows setting of status page templates. Whenever such page needs to be served, a Lookup is done for a template named by the code. Eg: "404". A generic template named "error" can be provided and will be used if there is no status-specific template defined.
If Tmpl is `nil` or no templates are found using above Lookup scheme, `DefaultErrTmpl` will be used.
type Provider ¶ added in v0.2.0
type Provider interface {
// Request returns the incomming http Request object
Request() *http.Request
Status() Status
Message() string
// String returns the status code, status text and message in a single string.
// For example: "400 Bad Request: Parsing form data"
String() string
}
Provider of data to templates
Source Files