Add support for Gitea webhooks

gitea/gitea.go

@@ -0,0 +1,199 @@
+package gitea
+
+import (
+	structs "code.gitea.io/gitea/modules/structs"
+	"crypto/hmac"
+	"crypto/sha1"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/http"
+)
+
+// parse errors
+var (
+	ErrEventNotSpecifiedToParse  = errors.New("no Event specified to parse")
+	ErrInvalidHTTPMethod         = errors.New("invalid HTTP Method")
+	ErrMissingGiteaEventHeader   = errors.New("missing X-Gitea-Event Header")
+	ErrMissingHubSignatureHeader = errors.New("missing X-Hub-Signature Header")
+	ErrEventNotFound             = errors.New("event not defined to be parsed")
+	ErrParsingPayload            = errors.New("error parsing payload")
+	ErrHMACVerificationFailed    = errors.New("HMAC verification failed")
+)
+
+// Event defines a Gitea hook event type
+type Event string
+
+// Gitea hook types
+const (
+	CreateEvent               Event = "create"
+	DeleteEvent               Event = "delete"
+	ForkEvent                 Event = "fork"
+	IssuesEvent               Event = "issues"
+	IssueAssignEvent          Event = "issue_assign"
+	IssueLabelEvent           Event = "issue_label"
+	IssueMilestoneEvent       Event = "issue_milestone"
+	IssueCommentEvent         Event = "issue_comment"
+	PushEvent                 Event = "push"
+	PullRequestEvent          Event = "pull_request"
+	PullRequestAssignEvent    Event = "pull_request_assign"
+	PullRequestLabelEvent     Event = "pull_request_label"
+	PullRequestMilestoneEvent Event = "pull_request_milestone"
+	PullRequestCommentEvent   Event = "pull_request_comment"
+	PullRequestReviewEvent    Event = "pull_request_review"
+	PullRequestSyncEvent      Event = "pull_request_sync"
+	RepositoryEvent           Event = "repository"
+	ReleaseEvent              Event = "release"
+	PackageEvent              Event = "package"
+)
+
+// EventSubtype defines a GitHub Hook Event subtype
+type EventSubtype string
+
+// Gitea hook event subtypes
+const (
+	NoSubtype     EventSubtype = ""
+	BranchSubtype EventSubtype = "branch"
+	TagSubtype    EventSubtype = "tag"
+	PullSubtype   EventSubtype = "pull"
+	IssueSubtype  EventSubtype = "issues"
+)
+
+// Option is a configuration option for the webhook
+type Option func(*Webhook) error
+
+// Options is a namespace var for configuration options
+var Options = WebhookOptions{}
+
+// WebhookOptions is a namespace for configuration option methods
+type WebhookOptions struct{}
+
+// Secret registers the Gitea secret
+func (WebhookOptions) Secret(secret string) Option {
+	return func(hook *Webhook) error {
+		hook.secret = secret
+		return nil
+	}
+}
+
+// Webhook instance contains all methods needed to process events
+type Webhook struct {
+	secret string
+}
+
+// New creates and returns a WebHook instance denoted by the Provider type
+func New(options ...Option) (*Webhook, error) {
+	hook := new(Webhook)
+	for _, opt := range options {
+		if err := opt(hook); err != nil {
+			return nil, errors.New("Error applying Option")
+		}
+	}
+	return hook, nil
+}
+
+// Parse verifies and parses the events specified and returns the payload object or an error
+func (hook Webhook) Parse(r *http.Request, events ...Event) (interface{}, error) {
+	defer func() {
+		_, _ = io.Copy(ioutil.Discard, r.Body)
+		_ = r.Body.Close()
+	}()
+
+	if len(events) == 0 {
+		return nil, ErrEventNotSpecifiedToParse
+	}
+	if r.Method != http.MethodPost {
+		return nil, ErrInvalidHTTPMethod
+	}
+
+	event := r.Header.Get("X-Gitea-Event")
+	if event == "" {
+		return nil, ErrMissingGiteaEventHeader
+	}
+	giteaEvent := Event(event)
+
+	var found bool
+	for _, evt := range events {
+		if evt == giteaEvent {
+			found = true
+			break
+		}
+	}
+	// event not defined to be parsed
+	if !found {
+		return nil, ErrEventNotFound
+	}
+
+	payload, err := ioutil.ReadAll(r.Body)
+	if err != nil || len(payload) == 0 {
+		return nil, ErrParsingPayload
+	}
+
+	// If we have a Secret set, we should check the MAC
+	if len(hook.secret) > 0 {
+		signature := r.Header.Get("X-Hub-Signature")
+		if len(signature) == 0 {
+			return nil, ErrMissingHubSignatureHeader
+		}
+		mac := hmac.New(sha1.New, []byte(hook.secret))
+		_, _ = mac.Write(payload)
+		expectedMAC := hex.EncodeToString(mac.Sum(nil))
+
+		if !hmac.Equal([]byte(signature[5:]), []byte(expectedMAC)) {
+			return nil, ErrHMACVerificationFailed
+		}
+	}
+
+	switch giteaEvent {
+	case CreateEvent:
+		var pl structs.CreatePayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case DeleteEvent:
+		var pl structs.DeletePayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case ForkEvent:
+		var pl structs.ForkPayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case IssuesEvent, IssueAssignEvent, IssueLabelEvent, IssueMilestoneEvent:
+		var pl structs.IssuePayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case IssueCommentEvent, PullRequestCommentEvent:
+		var pl structs.IssueCommentPayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case PushEvent:
+		var pl structs.PushPayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case PullRequestEvent, PullRequestAssignEvent, PullRequestLabelEvent,
+		PullRequestMilestoneEvent, PullRequestSyncEvent:
+		var pl structs.PullRequestPayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case PullRequestReviewEvent:
+		var pl structs.PullRequestPayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case RepositoryEvent:
+		var pl structs.RepositoryPayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case ReleaseEvent:
+		var pl structs.ReleasePayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case PackageEvent:
+		var pl structs.PackagePayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	default:
+		return nil, fmt.Errorf("unknown event %s", giteaEvent)
+	}
+}

go.mod

@@ -3,6 +3,7 @@ module github.com/go-playground/webhooks/v6
 go 1.15
 
 require (
+	code.gitea.io/gitea v1.17.4
 	github.com/gogits/go-gogs-client v0.0.0-20200905025246-8bb8a50cb355
-	github.com/stretchr/testify v1.6.1
+	github.com/stretchr/testify v1.8.0
 )