feat: add twitch graphql streamer resolution

2026-04-28 23:01:26 +02:00
parent 37ece958f3
commit 2f81173f1e
11 changed files with 928 additions and 31 deletions
@@ -0,0 +1,156 @@
+// client.go defines the authenticated Twitch GraphQL transport layer.
+// It owns request encoding, session header wiring, and response decoding
+// so higher-level Twitch services can issue typed operations without repeating HTTP logic.
+package gql
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+)
+
+const DefaultEndpoint = "https://gql.twitch.tv/gql"
+
+// Session carries the authenticated Twitch headers needed for GraphQL requests.
+type Session struct {
+	AccessToken string
+	ClientID    string
+	DeviceID    string
+	UserAgent   string
+}
+
+// Client posts authenticated GraphQL requests to Twitch.
+type Client struct {
+	HTTPClient *http.Client
+	Endpoint   string
+	Session    Session
+}
+
+// Error is one entry in a GraphQL errors list.
+type Error struct {
+	Message string `json:"message"`
+}
+
+// StatusError reports a non-200 HTTP response together with its response body.
+type StatusError struct {
+	StatusCode int
+	Body       string
+}
+
+// Error formats the HTTP status failure in a way that preserves the response body.
+func (e *StatusError) Error() string {
+	body := strings.TrimSpace(e.Body)
+	if body == "" {
+		return fmt.Sprintf("graphql status %d", e.StatusCode)
+	}
+	return fmt.Sprintf("graphql status %d: %s", e.StatusCode, body)
+}
+
+// Do executes one Twitch GraphQL request and decodes its data payload into out.
+func (c *Client) Do(ctx context.Context, request Request, out any) error {
+	if err := c.Validate(); err != nil {
+		return err
+	}
+
+	var body bytes.Buffer
+	if err := json.NewEncoder(&body).Encode(request); err != nil {
+		return fmt.Errorf("encode graphql request %s: %w", request.operationLabel(), err)
+	}
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, c.endpoint(), &body)
+	if err != nil {
+		return err
+	}
+	req.Header.Set("Accept", "application/json")
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Authorization", "OAuth "+c.Session.AccessToken)
+	req.Header.Set("Client-Id", c.Session.ClientID)
+	req.Header.Set("User-Agent", c.Session.UserAgent)
+	req.Header.Set("X-Device-Id", c.Session.DeviceID)
+
+	resp, err := c.httpClient().Do(req)
+	if err != nil {
+		return fmt.Errorf("post graphql %s: %w", request.operationLabel(), err)
+	}
+	defer resp.Body.Close()
+
+	respBody, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return fmt.Errorf("read graphql %s response: %w", request.operationLabel(), err)
+	}
+	if resp.StatusCode != http.StatusOK {
+		return &StatusError{StatusCode: resp.StatusCode, Body: string(respBody)}
+	}
+
+	var envelope struct {
+		Data   json.RawMessage `json:"data"`
+		Errors []Error         `json:"errors,omitempty"`
+	}
+	if err := json.Unmarshal(respBody, &envelope); err != nil {
+		return fmt.Errorf("parse graphql %s response: %w", request.operationLabel(), err)
+	}
+	if len(envelope.Errors) > 0 {
+		return fmt.Errorf("graphql %s returned errors: %s", request.operationLabel(), formatErrors(envelope.Errors))
+	}
+	if len(envelope.Data) == 0 || bytes.Equal(envelope.Data, []byte("null")) {
+		return fmt.Errorf("graphql %s response missing data", request.operationLabel())
+	}
+	if out == nil {
+		return nil
+	}
+	if err := json.Unmarshal(envelope.Data, out); err != nil {
+		return fmt.Errorf("decode graphql %s data: %w", request.operationLabel(), err)
+	}
+	return nil
+}
+
+// formatErrors joins GraphQL error messages into one readable string.
+func formatErrors(errs []Error) string {
+	parts := make([]string, 0, len(errs))
+	for _, err := range errs {
+		if err.Message != "" {
+			parts = append(parts, err.Message)
+		}
+	}
+	if len(parts) == 0 {
+		return "unknown error"
+	}
+	return strings.Join(parts, "; ")
+}
+
+// Validate rejects incomplete session configuration before any request is sent.
+func (c *Client) Validate() error {
+	switch {
+	case c.Session.AccessToken == "":
+		return errors.New("missing access token")
+	case c.Session.ClientID == "":
+		return errors.New("missing client id")
+	case c.Session.DeviceID == "":
+		return errors.New("missing device id")
+	case c.Session.UserAgent == "":
+		return errors.New("missing user agent")
+	default:
+		return nil
+	}
+}
+
+// httpClient returns the configured HTTP client or the default client.
+func (c *Client) httpClient() *http.Client {
+	if c.HTTPClient != nil {
+		return c.HTTPClient
+	}
+	return http.DefaultClient
+}
+
+// endpoint returns the configured GraphQL endpoint or the default Twitch endpoint.
+func (c *Client) endpoint() string {
+	if c.Endpoint != "" {
+		return c.Endpoint
+	}
+	return DefaultEndpoint
+}