// TopicsUpdateJSON responds to: PUT/PATCH /topics/:id. This will only be
// called when the user requested a JSON response.
func TopicsUpdateJSON(res http.ResponseWriter, req *http.Request) {
var str, value string
var p *params
if p = getFromBody(req); p == nil {
lib.JSONError(res)
return
}
// Execute the update query. Depending on the given parameters this will be
// just a plain rename, or a full update.
if value = p.Name; value == "" {
str = "contents"
if value = p.Contents; value == "" {
lib.JSONError(res)
return
}
} else {
str = "name"
}
// And finally send the JSON response.
var t Topic
str = fmt.Sprintf("update topics set %v=$1 where id=$2 returning *", str)
err := Db.SelectOne(&t, str, value, mux.Vars(req)["id"])
renderJSON(res, &t, err, true)
}
// TopicsCreateJSON responds to: POST /topics. This will only be called when
// the user requested a JSON response.
func TopicsCreateJSON(res http.ResponseWriter, req *http.Request) {
if p := getFromBody(req); p == nil {
lib.JSONError(res)
} else {
t, err := createTopic(p.Name)
renderJSON(res, t, err, false)
}
}
// Safely render and send a JSON response with the given topic. This function
// should be called after performing some operation that might return an error.
// This error from the previous operation is the third parameter. The fourth
// parameter tells this function to generate the Markdown code for this topic.
func renderJSON(res http.ResponseWriter, topic *Topic, err error, md bool) {
// Try to render the given Topic.
if err == nil {
if md {
topic.RenderMarkdown()
}
if b, err := json.Marshal(topic); err == nil {
fmt.Fprint(res, string(b))
res.Header().Set("Content-Type", "application/json")
return
}
}
// Render a generic error.
lib.JSONError(res)
}