ext/har: add HAR logger extension

Port HAR logging from abourget/goproxy to ext package.
Closes elazarl#609

ext/go.mod

@@ -2,8 +2,10 @@ module github.com/elazarl/goproxy/ext
 
 go 1.20
 
+replace github.com/elazarl/goproxy => ../
+
 require (
-	github.com/elazarl/goproxy v0.0.0-20241217120900-7711dfa3811c
+	github.com/elazarl/goproxy v0.0.0
 	golang.org/x/net v0.33.0
 	golang.org/x/text v0.21.0
 )

ext/go.sum

@@ -1,5 +1,3 @@
-github.com/elazarl/goproxy v0.0.0-20241217120900-7711dfa3811c h1:yWAGp1CjD1mQGLUsADqPn5s1n2AkGAX33XLDUgoXzyo=
-github.com/elazarl/goproxy v0.0.0-20241217120900-7711dfa3811c/go.mod h1:P73liMk9TZCyF9fXG/RyMeSizmATvpvy3ZS61/1eXn4=
 golang.org/x/net v0.33.0 h1:74SYHlV8BIgHIFC/LrYkOGIwL19eTYXQ5wc6TBuO36I=
 golang.org/x/net v0.33.0/go.mod h1:HXLR5J+9DxmrqMwG9qjGCxZ+zKXxBru04zlTvWlWuN4=
 golang.org/x/text v0.21.0 h1:zyQAAkrwaneQ066sspRyJaG9VNi/YJ1NfzcGB3hZ/qo=

ext/har/logger.go

@@ -0,0 +1,110 @@
+package har
+
+
+import (
+    "encoding/json"
+    "net/http"
+    "os"
+    "sync"
+    "time"
+
+    "github.com/elazarl/goproxy"
+)
+
+// Logger implements a HAR logging extension for goproxy
+type Logger struct {
+	mu             sync.Mutex
+	har            *Har
+	captureContent bool
+}
+
+// NewLogger creates a new HAR logger instance
+func NewLogger() *Logger {
+	return &Logger{
+		har: New(),
+	}
+}
+
+// OnRequest handles incoming HTTP requests
+func (l *Logger) OnRequest(req *http.Request, ctx *goproxy.ProxyCtx) (*http.Request, *http.Response) {
+	// Store the start time in context for later use
+	if ctx != nil {
+		ctx.UserData = time.Now()
+	}
+	return req, nil
+}
+
+// OnResponse handles HTTP responses
+func (l *Logger) OnResponse(resp *http.Response, ctx *goproxy.ProxyCtx) *http.Response {
+	if resp == nil || ctx == nil || ctx.Req == nil || ctx.UserData == nil {
+		return resp
+	}
+
+	startTime, ok := ctx.UserData.(time.Time)
+	if !ok {
+		return resp
+	}
+
+	// Create HAR entry
+	entry := Entry{
+		StartedDateTime: startTime,
+		Time:           time.Since(startTime).Milliseconds(),
+		Request:        ParseRequest(ctx.Req, l.captureContent),
+		Response:       ParseResponse(resp, l.captureContent),
+		Cache:          Cache{},
+		Timings: Timings{
+			Send:    0,
+			Wait:    time.Since(startTime).Milliseconds(),
+			Receive: 0,
+		},
+	}
+
+	// Add server IP
+	entry.FillIPAddress(ctx.Req)
+
+	// Add to HAR log thread-safely
+	l.mu.Lock()
+	l.har.AppendEntry(entry)
+	l.mu.Unlock()
+
+	return resp
+}
+
+// SetCaptureContent enables or disables request/response body capture
+func (l *Logger) SetCaptureContent(capture bool) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	l.captureContent = capture
+}
+
+// SaveToFile writes the current HAR log to a file
+func (l *Logger) SaveToFile(filename string) error {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+
+	file, err := os.Create(filename)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	encoder := json.NewEncoder(file)
+	encoder.SetIndent("", "  ")
+	return encoder.Encode(l.har)
+}
+
+// Clear resets the HAR log
+func (l *Logger) Clear() {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	l.har = New()
+}
+
+// GetEntries returns a copy of the current HAR entries
+func (l *Logger) GetEntries() []Entry {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	entries := make([]Entry, len(l.har.Log.Entries))
+	copy(entries, l.har.Log.Entries)
+	return entries
+}

ext/har/logger_test.go

@@ -0,0 +1,114 @@
+
+package har_test
+
+import (
+    "bytes"
+    "encoding/json"
+    "io"
+    "net/http"
+    "net/http/httptest"
+    "net/url"
+    "os"
+    "testing"
+
+    "github.com/elazarl/goproxy"
+    "github.com/elazarl/goproxy/ext/har"
+)
+
+type ConstantHandler string
+
+func (h ConstantHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+    io.WriteString(w, string(h))
+}
+
+func oneShotProxy(proxy *goproxy.ProxyHttpServer) (client *http.Client, s *httptest.Server) {
+    s = httptest.NewServer(proxy)
+
+    proxyUrl, _ := url.Parse(s.URL)
+    tr := &http.Transport{Proxy: http.ProxyURL(proxyUrl)}
+    client = &http.Client{Transport: tr}
+    return
+}
+
+func TestHarLogger(t *testing.T) {
+    // Create a response we expect
+    expected := "hello world"
+    background := httptest.NewServer(ConstantHandler(expected))
+    defer background.Close()
+
+    // Set up the proxy with HAR logger
+    proxy := goproxy.NewProxyHttpServer()
+    logger := har.NewLogger()
+    logger.SetCaptureContent(true)
+
+    proxy.OnRequest().DoFunc(logger.OnRequest)
+    proxy.OnResponse().DoFunc(logger.OnResponse)
+
+    client, proxyserver := oneShotProxy(proxy)
+    defer proxyserver.Close()
+
+    // Make a request
+    resp, err := client.Get(background.URL)
+    if err != nil {
+        t.Fatal(err)
+    }
+
+    // Read the response
+    msg, err := io.ReadAll(resp.Body)
+    if err != nil {
+        t.Fatal(err)
+    }
+    resp.Body.Close()
+
+    if string(msg) != expected {
+        t.Errorf("Expected '%s', actual '%s'", expected, string(msg))
+    }
+
+    // Test POST request with content
+    postData := "test=value"
+    req, err := http.NewRequest("POST", background.URL, bytes.NewBufferString(postData))
+    if err != nil {
+        t.Fatal(err)
+    }
+    req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+
+    resp, err = client.Do(req)
+    if err != nil {
+        t.Fatal(err)
+    }
+    resp.Body.Close()
+
+    // Save HAR file and verify content
+    tmpfile := "test.har"
+    err = logger.SaveToFile(tmpfile)
+    if err != nil {
+        t.Fatal(err)
+    }
+    defer os.Remove(tmpfile)
+
+    // Read and verify HAR content
+    harData, err := os.ReadFile(tmpfile)
+    if err != nil {
+        t.Fatal(err)
+    }
+
+    var harLog har.Har
+    if err := json.Unmarshal(harData, &harLog); err != nil {
+        t.Fatal(err)
+    }
+
+    // Verify we captured both requests
+    if len(harLog.Log.Entries) != 2 {
+        t.Errorf("Expected 2 entries in HAR log, got %d", len(harLog.Log.Entries))
+    }
+
+    // Verify GET request
+    if harLog.Log.Entries[0].Request.Method != "GET" {
+        t.Errorf("Expected GET request, got %s", harLog.Log.Entries[0].Request.Method)
+    }
+
+    // Verify POST request
+    if harLog.Log.Entries[1].Request.Method != "POST" {
+        t.Errorf("Expected POST request, got %s", harLog.Log.Entries[1].Request.Method)
+    }
+}