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 +639,23 @@ func createLLM() (llms.Model, error) {
 		if openaiAPIKey == "" {
 			return nil, fmt.Errorf("OpenAI API key is not set")
 		}
+
+		// 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 openai.New(
 			openai.WithModel(llmModel),
 			openai.WithToken(openaiAPIKey),
+			openai.WithHTTPClient(httpClient),
 		)
 	case "ollama":
 		host := os.Getenv("OLLAMA_HOST")
@@ -663,9 +677,23 @@ func createVisionLLM() (llms.Model, error) {
 		if openaiAPIKey == "" {
 			return nil, fmt.Errorf("OpenAI API key is not set")
 		}
+
+		// 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 openai.New(
 			openai.WithModel(visionLlmModel),
 			openai.WithToken(openaiAPIKey),
+			openai.WithHTTPClient(httpClient),
 		)
 	case "ollama":
 		host := os.Getenv("OLLAMA_HOST")
@@ -681,3 +709,17 @@ func createVisionLLM() (llms.Model, error) {
 		return nil, nil
 	}
 }
+
+// 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)
+}