2 files changed, 176 insertions, 0 deletions
diff --git a/services/webhook/shared/img.go b/services/webhook/shared/img.go
new file mode 100644
index 0000000..2d65ba4
--- /dev/null
+++ b/services/webhook/shared/img.go
@@ -0,0 +1,15 @@
+package shared
+
+import (
+	"html"
+	"html/template"
+	"strconv"
+
+	"code.gitea.io/gitea/modules/setting"
+)
+
+func ImgIcon(name string, size int) template.HTML {
+	s := strconv.Itoa(size)
+	src := html.EscapeString(setting.StaticURLPrefix + "/assets/img/" + name)
+	return template.HTML(`<img width="` + s + `" height="` + s + `" src="` + src + `">`)
+}
diff --git a/services/webhook/shared/payloader.go b/services/webhook/shared/payloader.go
new file mode 100644
index 0000000..cf0bfa8
--- /dev/null
+++ b/services/webhook/shared/payloader.go
@@ -0,0 +1,161 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package shared
+
+import (
+	"bytes"
+	"crypto/hmac"
+	"crypto/sha1"
+	"crypto/sha256"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+
+	webhook_model "code.gitea.io/gitea/models/webhook"
+	"code.gitea.io/gitea/modules/json"
+	api "code.gitea.io/gitea/modules/structs"
+	webhook_module "code.gitea.io/gitea/modules/webhook"
+)
+
+var ErrPayloadTypeNotSupported = errors.New("unsupported webhook event")
+
+// PayloadConvertor defines the interface to convert system payload to webhook payload
+type PayloadConvertor[T any] interface {
+	Create(*api.CreatePayload) (T, error)
+	Delete(*api.DeletePayload) (T, error)
+	Fork(*api.ForkPayload) (T, error)
+	Issue(*api.IssuePayload) (T, error)
+	IssueComment(*api.IssueCommentPayload) (T, error)
+	Push(*api.PushPayload) (T, error)
+	PullRequest(*api.PullRequestPayload) (T, error)
+	Review(*api.PullRequestPayload, webhook_module.HookEventType) (T, error)
+	Repository(*api.RepositoryPayload) (T, error)
+	Release(*api.ReleasePayload) (T, error)
+	Wiki(*api.WikiPayload) (T, error)
+	Package(*api.PackagePayload) (T, error)
+}
+
+func convertUnmarshalledJSON[T, P any](convert func(P) (T, error), data []byte) (T, error) {
+	var p P
+	if err := json.Unmarshal(data, &p); err != nil {
+		var t T
+		return t, fmt.Errorf("could not unmarshal payload: %w", err)
+	}
+	return convert(p)
+}
+
+func NewPayload[T any](rc PayloadConvertor[T], data []byte, event webhook_module.HookEventType) (T, error) {
+	switch event {
+	case webhook_module.HookEventCreate:
+		return convertUnmarshalledJSON(rc.Create, data)
+	case webhook_module.HookEventDelete:
+		return convertUnmarshalledJSON(rc.Delete, data)
+	case webhook_module.HookEventFork:
+		return convertUnmarshalledJSON(rc.Fork, data)
+	case webhook_module.HookEventIssues, webhook_module.HookEventIssueAssign, webhook_module.HookEventIssueLabel, webhook_module.HookEventIssueMilestone:
+		return convertUnmarshalledJSON(rc.Issue, data)
+	case webhook_module.HookEventIssueComment, webhook_module.HookEventPullRequestComment:
+		// previous code sometimes sent s.PullRequest(p.(*api.PullRequestPayload))
+		// however I couldn't find in notifier.go such a payload with an HookEvent***Comment event
+
+		// History (most recent first):
+		//  - refactored in https://github.com/go-gitea/gitea/pull/12310
+		//  - assertion added in https://github.com/go-gitea/gitea/pull/12046
+		//  - issue raised in https://github.com/go-gitea/gitea/issues/11940#issuecomment-645713996
+		//    > That's because for HookEventPullRequestComment event, some places use IssueCommentPayload and others use PullRequestPayload
+
+		// In modules/actions/workflows.go:183 the type assertion is always payload.(*api.IssueCommentPayload)
+		return convertUnmarshalledJSON(rc.IssueComment, data)
+	case webhook_module.HookEventPush:
+		return convertUnmarshalledJSON(rc.Push, data)
+	case webhook_module.HookEventPullRequest, webhook_module.HookEventPullRequestAssign, webhook_module.HookEventPullRequestLabel,
+		webhook_module.HookEventPullRequestMilestone, webhook_module.HookEventPullRequestSync, webhook_module.HookEventPullRequestReviewRequest:
+		return convertUnmarshalledJSON(rc.PullRequest, data)
+	case webhook_module.HookEventPullRequestReviewApproved, webhook_module.HookEventPullRequestReviewRejected, webhook_module.HookEventPullRequestReviewComment:
+		return convertUnmarshalledJSON(func(p *api.PullRequestPayload) (T, error) {
+			return rc.Review(p, event)
+		}, data)
+	case webhook_module.HookEventRepository:
+		return convertUnmarshalledJSON(rc.Repository, data)
+	case webhook_module.HookEventRelease:
+		return convertUnmarshalledJSON(rc.Release, data)
+	case webhook_module.HookEventWiki:
+		return convertUnmarshalledJSON(rc.Wiki, data)
+	case webhook_module.HookEventPackage:
+		return convertUnmarshalledJSON(rc.Package, data)
+	}
+	var t T
+	return t, fmt.Errorf("newPayload unsupported event: %s", event)
+}
+
+func NewJSONRequest[T any](pc PayloadConvertor[T], w *webhook_model.Webhook, t *webhook_model.HookTask, withDefaultHeaders bool) (*http.Request, []byte, error) {
+	payload, err := NewPayload(pc, []byte(t.PayloadContent), t.EventType)
+	if err != nil {
+		return nil, nil, err
+	}
+	return NewJSONRequestWithPayload(payload, w, t, withDefaultHeaders)
+}
+
+func NewJSONRequestWithPayload(payload any, w *webhook_model.Webhook, t *webhook_model.HookTask, withDefaultHeaders bool) (*http.Request, []byte, error) {
+	body, err := json.MarshalIndent(payload, "", "  ")
+	if err != nil {
+		return nil, nil, err
+	}
+
+	method := w.HTTPMethod
+	if method == "" {
+		method = http.MethodPost
+	}
+
+	req, err := http.NewRequest(method, w.URL, bytes.NewReader(body))
+	if err != nil {
+		return nil, nil, err
+	}
+	req.Header.Set("Content-Type", "application/json")
+
+	if withDefaultHeaders {
+		return req, body, AddDefaultHeaders(req, []byte(w.Secret), t, body)
+	}
+	return req, body, nil
+}
+
+// AddDefaultHeaders adds the X-Forgejo, X-Gitea, X-Gogs, X-Hub, X-GitHub headers to the given request
+func AddDefaultHeaders(req *http.Request, secret []byte, t *webhook_model.HookTask, payloadContent []byte) error {
+	var signatureSHA1 string
+	var signatureSHA256 string
+	if len(secret) > 0 {
+		sig1 := hmac.New(sha1.New, secret)
+		sig256 := hmac.New(sha256.New, secret)
+		_, err := io.MultiWriter(sig1, sig256).Write(payloadContent)
+		if err != nil {
+			// this error should never happen, since the hashes are writing to []byte and always return a nil error.
+			return fmt.Errorf("prepareWebhooks.sigWrite: %w", err)
+		}
+		signatureSHA1 = hex.EncodeToString(sig1.Sum(nil))
+		signatureSHA256 = hex.EncodeToString(sig256.Sum(nil))
+	}
+
+	event := t.EventType.Event()
+	eventType := string(t.EventType)
+	req.Header.Add("X-Forgejo-Delivery", t.UUID)
+	req.Header.Add("X-Forgejo-Event", event)
+	req.Header.Add("X-Forgejo-Event-Type", eventType)
+	req.Header.Add("X-Forgejo-Signature", signatureSHA256)
+	req.Header.Add("X-Gitea-Delivery", t.UUID)
+	req.Header.Add("X-Gitea-Event", event)
+	req.Header.Add("X-Gitea-Event-Type", eventType)
+	req.Header.Add("X-Gitea-Signature", signatureSHA256)
+	req.Header.Add("X-Gogs-Delivery", t.UUID)
+	req.Header.Add("X-Gogs-Event", event)
+	req.Header.Add("X-Gogs-Event-Type", eventType)
+	req.Header.Add("X-Gogs-Signature", signatureSHA256)
+	req.Header.Add("X-Hub-Signature", "sha1="+signatureSHA1)
+	req.Header.Add("X-Hub-Signature-256", "sha256="+signatureSHA256)
+	req.Header["X-GitHub-Delivery"] = []string{t.UUID}
+	req.Header["X-GitHub-Event"] = []string{event}
+	req.Header["X-GitHub-Event-Type"] = []string{eventType}
+	return nil
+}