// responseWriter sets the proper headers and status code, and
// writes a JSON-encoded response to the client.
func responseWriter(c siesta.Context, w http.ResponseWriter, r *http.Request,
quit func()) {
// Set the request ID header.
if requestID := c.Get("request-id"); requestID != nil {
w.Header().Set("X-Request-ID", requestID.(string))
}
// Set the content type.
w.Header().Set("Content-Type", "application/json")
enc := json.NewEncoder(w)
// If we have a status code set in the context,
// send that in the header.
//
// Go defaults to 200 OK.
statusCode := c.Get("status-code")
if statusCode != nil {
statusCodeInt := statusCode.(int)
w.WriteHeader(statusCodeInt)
}
// Check to see if we have some sort of response.
response := c.Get("response")
if response != nil {
// We'll encode it as JSON without knowing
// what it exactly is.
enc.Encode(response)
}
// We're at the end of the middleware chain, so quit.
quit()
}
// responseGenerator converts response and/or error data passed through the
// context into a structured response.
func responseGenerator(c siesta.Context, w http.ResponseWriter, r *http.Request) {
response := apiResponse{}
if data := c.Get("data"); data != nil {
response.Data = data
}
if err := c.Get("error"); err != nil {
response.Error = err.(string)
}
c.Set("response", response)
}
// getResource is the function that handles the GET /resources/:resourceID route.
func getResource(c siesta.Context, w http.ResponseWriter, r *http.Request) {
// Context variables
requestID := c.Get("request-id").(string)
db := c.Get("db").(*DB)
user := c.Get("user").(string)
// Check parameters
var params siesta.Params
resourceID := params.Int("resourceID", -1, "Resource identifier")
err := params.Parse(r.Form)
if err != nil {
log.Printf("[Req %s] %v", requestID, err)
c.Set("error", err.Error())
c.Set("status-code", http.StatusBadRequest)
return
}
// Make sure we have a valid resource ID.
if *resourceID == -1 {
c.Set("error", "invalid or missing resource ID")
c.Set("status-code", http.StatusBadRequest)
return
}
resource, err := db.resource(user, *resourceID)
if err != nil {
c.Set("status-code", http.StatusNotFound)
c.Set("error", "not found")
return
}
c.Set("data", resource)
}
// authenticator reads the username from the HTTP basic authentication header
// and validates the token. It sets the "user" key in the context to the
// user associated with the token.
func authenticator(c siesta.Context, w http.ResponseWriter, r *http.Request,
quit func()) {
// Context variables
requestID := c.Get("request-id").(string)
db := c.Get("db").(*DB)
// Check for a token in the HTTP basic authentication username field.
token, _, ok := r.BasicAuth()
if ok {
user, err := db.validateToken(token)
if err != nil {
log.Printf("[Req %s] Did not provide a valid token", requestID)
c.Set("status-code", http.StatusUnauthorized)
c.Set("error", "invalid token")
quit()
return
}
log.Printf("[Req %s] Provided a token for: %s", requestID, user)
// Add the user to the context.
c.Set("user", user)
} else {
log.Printf("[Req %s] Did not provide a token", requestID)
c.Set("error", "token required")
c.Set("status-code", http.StatusUnauthorized)
// Exit the chain here.
quit()
return
}
}
// requestIdentifier generates a request ID and sets the "request-id"
// key in the context. It also logs the request ID and the requested URL.
func requestIdentifier(c siesta.Context, w http.ResponseWriter, r *http.Request) {
requestID := fmt.Sprintf("%x", rand.Int())
c.Set("request-id", requestID)
log.Printf("[Req %s] %s %s", requestID, r.Method, r.URL)
}