136 lines
4.3 KiB
Go
136 lines
4.3 KiB
Go
package webserver
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import (
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"encoding/json"
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"fmt"
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"net"
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"net/http"
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"time"
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"github.com/unpoller/unpoller/pkg/poller"
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)
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/* This file has the methods that help the content-methods. Shared helpers. */
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const (
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xPollerError = "X-Poller-Error"
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mimeJSON = "application/json"
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mimeHTML = "text/plain; charset=utf-8"
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)
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// basicAuth wraps web requests with simple auth (and logging).
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// Called on nearly every request.
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func (s *Server) basicAuth(handler http.HandlerFunc) http.HandlerFunc {
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return s.handleLog(func(w http.ResponseWriter, r *http.Request) {
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if s.Accounts.PasswordIsCorrect(r.BasicAuth()) {
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handler(w, r)
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return
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}
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w.Header().Set("WWW-Authenticate", `Basic realm="Enter Name and Password to Login!"`)
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w.WriteHeader(http.StatusUnauthorized)
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})
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}
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// handleLog writes an Apache-like log line. Called on every request.
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func (s *Server) handleLog(handler http.HandlerFunc) http.HandlerFunc {
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return func(w http.ResponseWriter, r *http.Request) {
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if r.URL.Scheme = "https"; r.TLS == nil {
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r.URL.Scheme = "http" // Set schema early in case another handler uses it.
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}
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// Use custom ResponseWriter to catch and log response data.
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response := &ResponseWriter{Writer: w, Start: time.Now()}
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handler(response, r) // Run provided handler with custom ResponseWriter.
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user, _, _ := r.BasicAuth()
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if user == "" {
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user = "-" // Only used for logs.
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}
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logf := s.Logf // Standard log.
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if response.Error != "" {
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logf = s.LogErrorf // Format an error log.
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response.Error = ` "` + response.Error + `"`
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}
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remote, _, err := net.SplitHostPort(r.RemoteAddr)
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if err != nil {
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remote = r.RemoteAddr
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}
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logf(`%s %s %s [%v] "%s %s://%s%s %s" %d %d "%s" "%s" %v%s`, remote, poller.AppName,
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user, response.Start.Format("01/02/2006:15:04:05 -07:00"), r.Method, r.URL.Scheme,
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r.Host, r.RequestURI, r.Proto, response.Code, response.Size, r.Referer(),
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r.UserAgent(), time.Since(response.Start).Round(time.Microsecond), response.Error)
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}
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}
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// handleMissing returns a blank 404.
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func (s *Server) handleMissing(w http.ResponseWriter, r *http.Request) {
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w.Header().Set("Content-Type", mimeHTML)
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w.WriteHeader(http.StatusNotFound)
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_, _ = w.Write([]byte("404 page not found\n"))
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}
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// handleError is a pass-off function when a request returns an error.
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func (s *Server) handleError(w http.ResponseWriter, err error) {
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w.Header().Set("Content-Type", mimeHTML)
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w.Header().Set(xPollerError, err.Error()) // signal
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w.WriteHeader(http.StatusInternalServerError)
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_, _ = w.Write([]byte(err.Error() + "\n"))
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}
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// handleDone is a pass-off function to finish a request.
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func (s *Server) handleDone(w http.ResponseWriter, b []byte, cType string) {
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w.Header().Set("Content-Type", cType)
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w.WriteHeader(http.StatusOK)
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_, _ = w.Write(append(b, []byte("\n")...))
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}
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// handleJSON sends a json-formatted data reply.
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func (s *Server) handleJSON(w http.ResponseWriter, data any) {
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b, err := json.Marshal(data)
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if err != nil {
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s.handleError(w, err)
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return
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}
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s.handleDone(w, b, mimeJSON)
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}
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/* Custom http.ResponseWriter interface method and struct overrides. */
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// ResponseWriter is used to override http.ResponseWriter in our http.FileServer.
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// This allows us to catch and log the response code, size and error; maybe others.
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type ResponseWriter struct {
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Code int
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Size int
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Error string
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Start time.Time
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Writer http.ResponseWriter
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}
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// Header sends a header to a client. Satisfies http.ResponseWriter interface.
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func (w *ResponseWriter) Header() http.Header {
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return w.Writer.Header()
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}
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// Write sends bytes to the client. Satisfies http.ResponseWriter interface.
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// This also adds the written byte count to our size total.
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func (w *ResponseWriter) Write(b []byte) (int, error) {
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size, err := w.Writer.Write(b)
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w.Size += size
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return size, fmt.Errorf("writing response: %w", err)
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}
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// WriteHeader sends an http StatusCode to a client. Satisfies http.ResponseWriter interface.
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// This custom override method also saves the status code, and any error message (for logs).
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func (w *ResponseWriter) WriteHeader(code int) {
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w.Error = w.Header().Get(xPollerError) // Catch and save any response error.
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w.Header().Del(xPollerError) // Delete the temporary signal header.
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w.Code = code // Save the status code.
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w.Writer.WriteHeader(code) // Pass the request through.
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}
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