feat: add custom HTTP transport with headers for OpenAI client (#245)

* feat: add custom HTTP transport with headers for OpenAI client

Closes #237

main.go

@@ -8,9 +8,9 @@ import (
 	"paperless-gpt/ocr"
 	"path/filepath"
 	"runtime"
-	"strconv"
 	"slices"
-	"strings" 
+	"strconv"
+	"strings"
 	"sync"
 	"text/template"
 	"time"
@@ -639,9 +639,11 @@ func createLLM() (llms.Model, error) {
 		if openaiAPIKey == "" {
 			return nil, fmt.Errorf("OpenAI API key is not set")
 		}
+
 		return openai.New(
 			openai.WithModel(llmModel),
 			openai.WithToken(openaiAPIKey),
+			openai.WithHTTPClient(createCustomHTTPClient()),
 		)
 	case "ollama":
 		host := os.Getenv("OLLAMA_HOST")
@@ -663,9 +665,11 @@ func createVisionLLM() (llms.Model, error) {
 		if openaiAPIKey == "" {
 			return nil, fmt.Errorf("OpenAI API key is not set")
 		}
+
 		return openai.New(
 			openai.WithModel(visionLlmModel),
 			openai.WithToken(openaiAPIKey),
+			openai.WithHTTPClient(createCustomHTTPClient()),
 		)
 	case "ollama":
 		host := os.Getenv("OLLAMA_HOST")
@@ -681,3 +685,33 @@ func createVisionLLM() (llms.Model, error) {
 		return nil, nil
 	}
 }
+
+func createCustomHTTPClient() *http.Client {
+	// Create custom transport that adds headers
+	customTransport := &headerTransport{
+		transport: http.DefaultTransport,
+		headers: map[string]string{
+			"X-Title": "paperless-gpt",
+		},
+	}
+
+	// Create custom client with the transport
+	httpClient := http.DefaultClient
+	httpClient.Transport = customTransport
+
+	return httpClient
+}
+
+// headerTransport is a custom http.RoundTripper that adds custom headers to requests
+type headerTransport struct {
+	transport http.RoundTripper
+	headers   map[string]string
+}
+
+// RoundTrip implements the http.RoundTripper interface
+func (t *headerTransport) RoundTrip(req *http.Request) (*http.Response, error) {
+	for key, value := range t.headers {
+		req.Header.Add(key, value)
+	}
+	return t.transport.RoundTrip(req)
+}

main_test.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"net/http"
+	"net/http/httptest"
 	"slices"
 	"testing"
 	"text/template"
@@ -175,3 +176,24 @@ func TestProcessAutoTagDocuments(t *testing.T) {
 		})
 	}
 }
+
+func TestCreateCustomHTTPClient(t *testing.T) {
+	// Create a test server
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// Verify custom header
+		assert.Equal(t, "paperless-gpt", r.Header.Get("X-Title"), "Expected X-Title header")
+		w.WriteHeader(http.StatusOK)
+	}))
+	defer server.Close()
+
+	// Get custom client
+	client := createCustomHTTPClient()
+	require.NotNil(t, client, "HTTP client should not be nil")
+
+	// Make a request
+	resp, err := client.Get(server.URL)
+	require.NoError(t, err, "Request should not fail")
+	defer resp.Body.Close()
+
+	assert.Equal(t, http.StatusOK, resp.StatusCode, "Expected 200 OK response")
+}