feat: add jobs worker and webhook core

backend/internal/webhook/webhook.go

@@ -0,0 +1,125 @@
+// Package webhook owns the generation-job callback byte and retry contract.
+package webhook
+
+import (
+	"context"
+	"crypto/hmac"
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"strings"
+	"time"
+
+	"git.nianxx.cn/wangxuming/NianAIGC/backend/internal/jobs"
+)
+
+const (
+	MaximumAttempts = 3
+	UserAgent       = "zhinian-aigc-webhook/1.0"
+)
+
+type Payload struct {
+	JobID          string         `json:"jobId"`
+	Status         jobs.Status    `json:"status"`
+	Capability     string         `json:"capability"`
+	OutputAssetIDs []string       `json:"outputAssetIds"`
+	Error          *jobs.JobError `json:"error,omitempty"`
+	UpdatedAt      string         `json:"updatedAt"`
+}
+
+func Body(job jobs.Job) ([]byte, error) {
+	outputIDs := job.OutputAssetIDs
+	if outputIDs == nil {
+		outputIDs = []string{}
+	}
+	payload := Payload{
+		JobID: job.ID, Status: job.Status, Capability: job.Capability,
+		OutputAssetIDs: outputIDs, Error: job.Error,
+		// JavaScript Date#toISOString always emits exactly three fractional
+		// digits. Keep those bytes stable because the HMAC covers them.
+		UpdatedAt: job.UpdatedAt.UTC().Format("2006-01-02T15:04:05.000Z"),
+	}
+	return json.Marshal(payload)
+}
+
+func Sign(body []byte, secret string) string {
+	secret = strings.TrimSpace(secret)
+	if secret == "" {
+		return ""
+	}
+	mac := hmac.New(sha256.New, []byte(secret))
+	_, _ = mac.Write(body)
+	return "sha256=" + hex.EncodeToString(mac.Sum(nil))
+}
+
+type Request struct {
+	URL     string
+	Body    []byte
+	Headers map[string]string
+}
+
+type Response struct {
+	Status int
+}
+
+type Sender interface {
+	Send(context.Context, Request) (Response, error)
+}
+
+type LastStatus struct {
+	OK          bool   `json:"ok"`
+	Status      int    `json:"status,omitempty"`
+	Error       string `json:"error,omitempty"`
+	AttemptedAt string `json:"attemptedAt"`
+}
+
+type Result struct {
+	Attempts   int
+	LastStatus *LastStatus
+}
+
+type Deliverer struct {
+	sender Sender
+	secret string
+	now    func() time.Time
+}
+
+func NewDeliverer(sender Sender, secret string, now func() time.Time) *Deliverer {
+	if now == nil {
+		now = time.Now
+	}
+	return &Deliverer{sender: sender, secret: secret, now: now}
+}
+
+func (deliverer *Deliverer) Deliver(ctx context.Context, job jobs.Job) (Result, error) {
+	if job.WebhookURL == "" {
+		return Result{Attempts: job.WebhookAttempts}, nil
+	}
+	if deliverer == nil || deliverer.sender == nil {
+		return Result{}, fmt.Errorf("webhook sender is not configured")
+	}
+	body, err := Body(job)
+	if err != nil {
+		return Result{}, err
+	}
+	headers := map[string]string{"Content-Type": "application/json", "User-Agent": UserAgent}
+	if signature := Sign(body, deliverer.secret); signature != "" {
+		headers["X-Zhinian-Signature"] = signature
+	}
+	result := Result{Attempts: job.WebhookAttempts}
+	for result.Attempts < MaximumAttempts {
+		result.Attempts++
+		attemptedAt := deliverer.now().UTC().Format(time.RFC3339Nano)
+		response, sendErr := deliverer.sender.Send(ctx, Request{URL: job.WebhookURL, Body: body, Headers: headers})
+		if sendErr != nil {
+			result.LastStatus = &LastStatus{OK: false, Error: sendErr.Error(), AttemptedAt: attemptedAt}
+			continue
+		}
+		result.LastStatus = &LastStatus{OK: response.Status >= 200 && response.Status < 300, Status: response.Status, AttemptedAt: attemptedAt}
+		if result.LastStatus.OK {
+			break
+		}
+	}
+	return result, nil
+}