Support get http header and x-ratelimit-* headers (#507)

* feat: add headers to http response

* feat: support rate limit headers

* fix: go lint

* fix: test coverage

* refactor streamReader

* refactor streamReader

* refactor: NewRateLimitHeaders to newRateLimitHeaders

* refactor: RateLimitHeaders Resets filed

* refactor: move RateLimitHeaders struct

chat_stream_test.go

@@ -1,15 +1,17 @@
 package openai_test
 
 import (
-	. "github.com/sashabaranov/go-openai"
-	"github.com/sashabaranov/go-openai/internal/test/checks"
-
 	"context"
 	"encoding/json"
 	"errors"
+	"fmt"
 	"io"
 	"net/http"
+	"strconv"
 	"testing"
+
+	. "github.com/sashabaranov/go-openai"
+	"github.com/sashabaranov/go-openai/internal/test/checks"
 )
 
 func TestChatCompletionsStreamWrongModel(t *testing.T) {
@@ -178,6 +180,87 @@ func TestCreateChatCompletionStreamError(t *testing.T) {
 	t.Logf("%+v\n", apiErr)
 }
 
+func TestCreateChatCompletionStreamWithHeaders(t *testing.T) {
+	client, server, teardown := setupOpenAITestServer()
+	defer teardown()
+	server.RegisterHandler("/v1/chat/completions", func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "text/event-stream")
+		w.Header().Set(xCustomHeader, xCustomHeaderValue)
+
+		// Send test responses
+		//nolint:lll
+		dataBytes := []byte(`data: {"error":{"message":"The server had an error while processing your request. Sorry about that!", "type":"server_ error", "param":null,"code":null}}`)
+		dataBytes = append(dataBytes, []byte("\n\ndata: [DONE]\n\n")...)
+
+		_, err := w.Write(dataBytes)
+		checks.NoError(t, err, "Write error")
+	})
+
+	stream, err := client.CreateChatCompletionStream(context.Background(), ChatCompletionRequest{
+		MaxTokens: 5,
+		Model:     GPT3Dot5Turbo,
+		Messages: []ChatCompletionMessage{
+			{
+				Role:    ChatMessageRoleUser,
+				Content: "Hello!",
+			},
+		},
+		Stream: true,
+	})
+	checks.NoError(t, err, "CreateCompletionStream returned error")
+	defer stream.Close()
+
+	value := stream.Header().Get(xCustomHeader)
+	if value != xCustomHeaderValue {
+		t.Errorf("expected %s to be %s", xCustomHeaderValue, value)
+	}
+}
+
+func TestCreateChatCompletionStreamWithRatelimitHeaders(t *testing.T) {
+	client, server, teardown := setupOpenAITestServer()
+	defer teardown()
+	server.RegisterHandler("/v1/chat/completions", func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "text/event-stream")
+		for k, v := range rateLimitHeaders {
+			switch val := v.(type) {
+			case int:
+				w.Header().Set(k, strconv.Itoa(val))
+			default:
+				w.Header().Set(k, fmt.Sprintf("%s", v))
+			}
+		}
+
+		// Send test responses
+		//nolint:lll
+		dataBytes := []byte(`data: {"error":{"message":"The server had an error while processing your request. Sorry about that!", "type":"server_ error", "param":null,"code":null}}`)
+		dataBytes = append(dataBytes, []byte("\n\ndata: [DONE]\n\n")...)
+
+		_, err := w.Write(dataBytes)
+		checks.NoError(t, err, "Write error")
+	})
+
+	stream, err := client.CreateChatCompletionStream(context.Background(), ChatCompletionRequest{
+		MaxTokens: 5,
+		Model:     GPT3Dot5Turbo,
+		Messages: []ChatCompletionMessage{
+			{
+				Role:    ChatMessageRoleUser,
+				Content: "Hello!",
+			},
+		},
+		Stream: true,
+	})
+	checks.NoError(t, err, "CreateCompletionStream returned error")
+	defer stream.Close()
+
+	headers := stream.GetRateLimitHeaders()
+	bs1, _ := json.Marshal(headers)
+	bs2, _ := json.Marshal(rateLimitHeaders)
+	if string(bs1) != string(bs2) {
+		t.Errorf("expected rate limit header %s to be %s", bs2, bs1)
+	}
+}
+
 func TestCreateChatCompletionStreamErrorWithDataPrefix(t *testing.T) {
 	client, server, teardown := setupOpenAITestServer()
 	defer teardown()

chat_test.go

@@ -21,6 +21,17 @@ const (
 	xCustomHeaderValue = "test"
 )
 
+var (
+	rateLimitHeaders = map[string]any{
+		"x-ratelimit-limit-requests":     60,
+		"x-ratelimit-limit-tokens":       150000,
+		"x-ratelimit-remaining-requests": 59,
+		"x-ratelimit-remaining-tokens":   149984,
+		"x-ratelimit-reset-requests":     "1s",
+		"x-ratelimit-reset-tokens":       "6m0s",
+	}
+)
+
 func TestChatCompletionsWrongModel(t *testing.T) {
 	config := DefaultConfig("whatever")
 	config.BaseURL = "http://localhost/v1"
@@ -97,6 +108,40 @@ func TestChatCompletionsWithHeaders(t *testing.T) {
 	}
 }
 
+// TestChatCompletionsWithRateLimitHeaders Tests the completions endpoint of the API using the mocked server.
+func TestChatCompletionsWithRateLimitHeaders(t *testing.T) {
+	client, server, teardown := setupOpenAITestServer()
+	defer teardown()
+	server.RegisterHandler("/v1/chat/completions", handleChatCompletionEndpoint)
+	resp, err := client.CreateChatCompletion(context.Background(), ChatCompletionRequest{
+		MaxTokens: 5,
+		Model:     GPT3Dot5Turbo,
+		Messages: []ChatCompletionMessage{
+			{
+				Role:    ChatMessageRoleUser,
+				Content: "Hello!",
+			},
+		},
+	})
+	checks.NoError(t, err, "CreateChatCompletion error")
+
+	headers := resp.GetRateLimitHeaders()
+	resetRequests := headers.ResetRequests.String()
+	if resetRequests != rateLimitHeaders["x-ratelimit-reset-requests"] {
+		t.Errorf("expected resetRequests %s to be %s", resetRequests, rateLimitHeaders["x-ratelimit-reset-requests"])
+	}
+	resetRequestsTime := headers.ResetRequests.Time()
+	if resetRequestsTime.Before(time.Now()) {
+		t.Errorf("unexpected reset requetsts: %v", resetRequestsTime)
+	}
+
+	bs1, _ := json.Marshal(headers)
+	bs2, _ := json.Marshal(rateLimitHeaders)
+	if string(bs1) != string(bs2) {
+		t.Errorf("expected rate limit header %s to be %s", bs2, bs1)
+	}
+}
+
 // TestChatCompletionsFunctions tests including a function call.
 func TestChatCompletionsFunctions(t *testing.T) {
 	client, server, teardown := setupOpenAITestServer()
@@ -311,6 +356,14 @@ func handleChatCompletionEndpoint(w http.ResponseWriter, r *http.Request) {
 	}
 	resBytes, _ = json.Marshal(res)
 	w.Header().Set(xCustomHeader, xCustomHeaderValue)
+	for k, v := range rateLimitHeaders {
+		switch val := v.(type) {
+		case int:
+			w.Header().Set(k, strconv.Itoa(val))
+		default:
+			w.Header().Set(k, fmt.Sprintf("%s", v))
+		}
+	}
 	fmt.Fprintln(w, string(resBytes))
 }
 

client.go

@@ -30,8 +30,12 @@ func (h *httpHeader) SetHeader(header http.Header) {
 	*h = httpHeader(header)
 }
 
-func (h httpHeader) Header() http.Header {
-	return http.Header(h)
+func (h *httpHeader) Header() http.Header {
+	return http.Header(*h)
+}
+
+func (h *httpHeader) GetRateLimitHeaders() RateLimitHeaders {
+	return newRateLimitHeaders(h.Header())
 }
 
 // NewClient creates new OpenAI API client.
@@ -156,6 +160,7 @@ func sendRequestStream[T streamable](client *Client, req *http.Request) (*stream
 		response:           resp,
 		errAccumulator:     utils.NewErrorAccumulator(),
 		unmarshaler:        &utils.JSONUnmarshaler{},
+		httpHeader:         httpHeader(resp.Header),
 	}, nil
 }
 

ratelimit.go

@@ -0,0 +1,43 @@
+package openai
+
+import (
+	"net/http"
+	"strconv"
+	"time"
+)
+
+// RateLimitHeaders struct represents Openai rate limits headers.
+type RateLimitHeaders struct {
+	LimitRequests     int       `json:"x-ratelimit-limit-requests"`
+	LimitTokens       int       `json:"x-ratelimit-limit-tokens"`
+	RemainingRequests int       `json:"x-ratelimit-remaining-requests"`
+	RemainingTokens   int       `json:"x-ratelimit-remaining-tokens"`
+	ResetRequests     ResetTime `json:"x-ratelimit-reset-requests"`
+	ResetTokens       ResetTime `json:"x-ratelimit-reset-tokens"`
+}
+
+type ResetTime string
+
+func (r ResetTime) String() string {
+	return string(r)
+}
+
+func (r ResetTime) Time() time.Time {
+	d, _ := time.ParseDuration(string(r))
+	return time.Now().Add(d)
+}
+
+func newRateLimitHeaders(h http.Header) RateLimitHeaders {
+	limitReq, _ := strconv.Atoi(h.Get("x-ratelimit-limit-requests"))
+	limitTokens, _ := strconv.Atoi(h.Get("x-ratelimit-limit-tokens"))
+	remainingReq, _ := strconv.Atoi(h.Get("x-ratelimit-remaining-requests"))
+	remainingTokens, _ := strconv.Atoi(h.Get("x-ratelimit-remaining-tokens"))
+	return RateLimitHeaders{
+		LimitRequests:     limitReq,
+		LimitTokens:       limitTokens,
+		RemainingRequests: remainingReq,
+		RemainingTokens:   remainingTokens,
+		ResetRequests:     ResetTime(h.Get("x-ratelimit-reset-requests")),
+		ResetTokens:       ResetTime(h.Get("x-ratelimit-reset-tokens")),
+	}
+}

stream_reader.go

@@ -27,6 +27,8 @@ type streamReader[T streamable] struct {
 	response       *http.Response
 	errAccumulator utils.ErrorAccumulator
 	unmarshaler    utils.Unmarshaler
+
+	httpHeader
 }
 
 func (stream *streamReader[T]) Recv() (response T, err error) {