Adds support for Bitbucket Server (#63)

bitbucket-server/bitbucketserver.go

@@ -0,0 +1,218 @@
+package bitbucketserver
+
+import (
+	"crypto/hmac"
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/http"
+)
+
+var (
+	ErrEventNotSpecifiedToParse  = errors.New("no Event specified to parse")
+	ErrInvalidHTTPMethod         = errors.New("invalid HTTP Method")
+	ErrMissingEventKeyHeader     = errors.New("missing X-Event-Key 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")
+)
+
+type Event string
+
+const (
+	RepositoryReferenceChangedEvent Event = "repo:refs_changed"
+	RepositoryModifiedEvent         Event = "repo:modified"
+	RepositoryForkedEvent           Event = "repo:forked"
+	RepositoryCommentAddedEvent     Event = "repo:comment:added"
+	RepositoryCommentEditedEvent    Event = "repo:comment:edited"
+	RepositoryCommentDeletedEvent   Event = "repo:comment:deleted"
+
+	PullRequestOpenedEvent   Event = "pr:opened"
+	PullRequestModifiedEvent Event = "pr:modified"
+	PullRequestMergedEvent   Event = "pr:merged"
+	PullRequestDeclinedEvent Event = "pr:declined"
+	PullRequestDeletedEvent  Event = "pr:deleted"
+
+	PullRequestReviewerUpdatedEvent    Event = "pr:reviewer:updated"
+	PullRequestReviewerApprovedEvent   Event = "pr:reviewer:approved"
+	PullRequestReviewerUnapprovedEvent Event = "pr:reviewer:unapproved"
+	PullRequestReviewerNeedsWorkEvent  Event = "pr:reviewer:needs_work"
+
+	PullRequestCommentAddedEvent   Event = "pr:comment:added"
+	PullRequestCommentEditedEvent  Event = "pr:comment:edited"
+	PullRequestCommentDeletedEvent Event = "pr:comment:deleted"
+
+	DiagnosticsPingEvent Event = "diagnostics:ping"
+)
+
+// 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 GitHub 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
+}
+
+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-Event-Key")
+	if event == "" {
+		return nil, ErrMissingEventKeyHeader
+	}
+
+	bitbucketEvent := Event(event)
+
+	var found bool
+	for _, evt := range events {
+		if evt == bitbucketEvent {
+			found = true
+			break
+		}
+	}
+	// event not defined to be parsed
+	if !found {
+		return nil, ErrEventNotFound
+	}
+
+	if bitbucketEvent == DiagnosticsPingEvent {
+		return DiagnosticsPingPayload{}, nil
+	}
+
+	payload, err := ioutil.ReadAll(r.Body)
+	if err != nil || len(payload) == 0 {
+		return nil, ErrParsingPayload
+	}
+
+	if len(hook.secret) > 0 {
+		signature := r.Header.Get("X-Hub-Signature")
+		if len(signature) == 0 {
+			return nil, ErrMissingHubSignatureHeader
+		}
+		mac := hmac.New(sha256.New, []byte(hook.secret))
+		_, _ = mac.Write(payload)
+		expectedMAC := hex.EncodeToString(mac.Sum(nil))
+
+		if !hmac.Equal([]byte(signature[7:]), []byte(expectedMAC)) {
+			return nil, ErrHMACVerificationFailed
+		}
+	}
+
+	switch bitbucketEvent {
+	case RepositoryReferenceChangedEvent:
+		var pl RepositoryReferenceChangedPayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case RepositoryModifiedEvent:
+		var pl RepositoryModifiedPayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case RepositoryForkedEvent:
+		var pl RepositoryForkedPayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case RepositoryCommentAddedEvent:
+		var pl RepositoryCommentAddedPayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case RepositoryCommentEditedEvent:
+		var pl RepositoryCommentEditedPayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case RepositoryCommentDeletedEvent:
+		var pl RepositoryCommentDeletedPayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case PullRequestOpenedEvent:
+		var pl PullRequestOpenedPayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case PullRequestModifiedEvent:
+		var pl PullRequestModifiedPayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case PullRequestMergedEvent:
+		var pl PullRequestMergedPayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case PullRequestDeclinedEvent:
+		var pl PullRequestDeclinedPayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case PullRequestDeletedEvent:
+		var pl PullRequestDeletedPayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case PullRequestReviewerUpdatedEvent:
+		var pl PullRequestReviewerUpdatedPayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case PullRequestReviewerApprovedEvent:
+		var pl PullRequestReviewerApprovedPayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case PullRequestReviewerUnapprovedEvent:
+		var pl PullRequestReviewerUnapprovedPayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case PullRequestReviewerNeedsWorkEvent:
+		var pl PullRequestReviewerNeedsWorkPayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case PullRequestCommentAddedEvent:
+		var pl PullRequestCommentAddedPayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case PullRequestCommentEditedEvent:
+		var pl PullRequestCommentEditedPayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	case PullRequestCommentDeletedEvent:
+		var pl PullRequestCommentDeletedPayload
+		err = json.Unmarshal([]byte(payload), &pl)
+		return pl, err
+	default:
+		return nil, fmt.Errorf("unknown event %s", bitbucketEvent)
+	}
+}