provider가 Request를 보내기 전에 서명하여 signature를 만들고 public key를 제공하여 받는 쪽에서 적절한 암호화 알고리즘을 통해 검증
Failure & Retries
HTTP Status Code 대응
2XX
성공한 것이므로 종료
3XX
webhook subscription 정보를 동적으로 수정할 것인지 결정 필요
fail으로 처리할 것인지 retry로 처리할 것인지 결정 필요
4XX
일반적으로 retry 해야 함
401, 404의 경우 일시적인 문제일 수 있으므로 즉시 처리하지 말아야 함
410이라면 즉시 처리
5XX
기본적으로 retry 하되 정해진 횟수나 시간 만큼만 하도록 설정
Failure 대응
Exponential Backoff
같은 webhook에 대해 retry를 할 때마다 간격을 점점 늘려나가며 하는 방법
일정 시간 간격 내지는 일정 횟수 제한을 두고 그 제한을 넘어가면 webhook consumer가 비정상인 것으로 간주하여 subscription 자체를 중단하게 설정
Claim Check
webhook에 실패할 경우 별도의 저장소에다가 저장해두고 나중에 확인할 수 있도록 하는 방법
저장된 webhook을 확인할 수 있게 별도의 URL을 미리 제공하여 webhook consumer가 필요할 때 찾아볼 수 있도록 하는 방법
정해진 횟수의 retry 이후 저장소에 저장. 이후 만료되기 전까지 정기적으로 저장된 webhook을 확인할 수 있는 URL을 전송하는 방법
Ensuring Ordered Delivery
webhook의 순서를 보장하기 위해선 일종의 sequence ID를 주는 방법이 있음
물론 이 경우엔 webhook consumer가 webhook을 받아서 재정렬하는 과정이 필요
Events
보통 name, payload 두 가지로 구성됨
Name
[Resource Name].[Sub Resource Name].[Event] 같은 형식으로 명명
Payload
Webhook의 리소스에 해당하는 REST API가 이미 있다면 webhook의 페이로드도 완전히 똑같이 만들어주는 편이 좋음
구현 사례
Slack
Incoming Webhooks와 Outgoing Webhooks 두 가지를 지원하고 있음
Rate Limits 존재
Incoming Webhooks
JSON 형식
슬랙 내부에 메세지를 보내기 위해서 사용
Outgoing Webhooks
특정 채널에서 특정 'trigger word'가 발생하였을 때 정해진 URL로 POST request를 보내주는 webhook
POST body
token=XXXXXXXXXXXXXXXXXX
team_id=T0001
team_domain=example
channel_id=C2147483705
channel_name=test
timestamp=1355517523.000005
user_id=U2147483697
user_name=Steve
text=googlebot: What is the air-speed velocity of an unladen swallow?
trigger_word=googlebot:
POST https://www.googleapis.com/calendar/v3/calendars/my_calendar@gmail.com/events/watchAuthorization: Bearer auth_token_for_current_userContent-Type: application/json{"id": "01234567-89ab-cdef-0123456789ab",// Your channel ID."type": "web_hook","address": "https://mydomain.com/notifications",// Your receiving URL.// ..."token": "target=myApp-myCalendarChannelDest",// (Optional) Your channel token."expiration": 1426325213000// (Optional) Your requested channel expiration time. }}
response
{"kind": "api#channel","id": "01234567-89ab-cdef-0123456789ab"", // ID you specified for this channel."resourceId": "o3hgv1538sdjfh",// ID of the watched resource. "resourceUri": "https://www.googleapis.com/calendar/v3/calendars/my_calendar@gmail.com/events", // Version-specific ID of the watched resource.
"token": "target=myApp-myCalendarChannelDest",// Present only if one was provided."expiration": 1426325213000,// Actual expiration time as Unix timestamp (in ms), if applicable.}
Sync
webhook이 시작되었음을 알림
Request
POST https://mydomain.com/notifications // Your receiving URL.
X-Goog-Channel-ID: channel-ID-value
X-Goog-Channel-Token: channel-token-value
X-Goog-Channel-Expiration: expiration-date-and-time // In human-readable format; present only if channel expires.
X-Goog-Resource-ID: identifier-for-the-watched-resource
X-Goog-Resource-URI: version-specific-URI-of-the-watched-resource
X-Goog-Resource-State: sync
X-Goog-Message-Number: 1
Notifications
실질적인 webhook
HTTPS POST
Request
POST https://mydomain.com/notifications // Your receiving URL.
Content-Type: application/json; utf-8
Content-Length: 0
X-Goog-Channel-ID: 4ba78bf0-6a47-11e2-bcfd-0800200c9a66
X-Goog-Channel-Token: 398348u3tu83ut8uu38
X-Goog-Channel-Expiration: Tue, 19 Nov 2013 01:13:52 GMT
X-Goog-Resource-ID: ret08u3rv24htgh289g
X-Goog-Resource-URI: https://www.googleapis.com/calendar/v3/calendars/my_calendar@gmail.com/events
X-Goog-Resource-State: exists
X-Goog-Message-Number: 10
POST https://www.googleapis.com/calendar/v3/channels/stopAuthorization: Bearer {auth_token_for_current_user}Content-Type: application/json{"id": "4ba78bf0-6a47-11e2-bcfd-0800200c9a66","resourceId": "ret08u3rv24htgh289g"}
Jira
webhook을 얻을 수 있는 쿼리 메소드 제공
등록
<JIRA_URL>/rest/webhooks/1.0/webhook
{"name": "my first webhook via rest","url": "http://www.example.com/webhooks","events": ["jira:issue_created","jira:issue_updated" ],"jqlFilter": "Project = JRA AND resolution = Fixed","excludeIssueDetails" : false}
해지
<JIRA_URL>/rest/webhooks/1.0/webhook/{id of the webhook}
쿼리
<JIRA_URL>/rest/webhooks/1.0/webhook
<JIRA_URL>/rest/webhooks/1.0/webhook/<webhook ID>
Webhook
{"id": 2,"timestamp": "2009-09-09T00:08:36.796-0500","issue": { "expand":"renderedFields,names,schema,transitions,operations,editmeta,changelog","id":"99291","self":"https://jira.atlassian.com/rest/api/2/issue/99291","key":"JRA-20002","fields":{"summary":"I feel the need for speed","created":"2009-12-16T23:46:10.612-0600","description":"Make the issue nav load 10x faster","labels":["UI","dialogue","move"],"priority":"Minor" } },"user": {"self":"https://jira.atlassian.com/rest/api/2/user?username=brollins","name":"brollins","emailAddress":"bryansemail at atlassian dot com","avatarUrls":{"16x16":"https://jira.atlassian.com/secure/useravatar?size=small&avatarId=10605","48x48":"https://jira.atlassian.com/secure/useravatar?avatarId=10605" },"displayName":"Bryan Rollins [Atlassian]","active":"true" },"changelog": {"items": [ {"toString":"A new summary.","to":null,"fromString":"What is going on here?????","from":null,"fieldtype":"jira","field":"summary" }, {"toString":"New Feature","to":"2","fromString":"Improvement","from":"4","fieldtype":"jira","field":"issuetype" } ],"id":10124 },"comment" : {"self":"https://jira.atlassian.com/rest/api/2/issue/10148/comment/252789","id":"252789","author":{"self":"https://jira.atlassian.com/rest/api/2/user?username=brollins","name":"brollins","emailAddress":"bryansemail@atlassian.com","avatarUrls":{"16x16":"https://jira.atlassian.com/secure/useravatar?size=small&avatarId=10605","48x48":"https://jira.atlassian.com/secure/useravatar?avatarId=10605" },"displayName":"Bryan Rollins [Atlassian]","active":true },"body":"Just in time for AtlasCamp!","updateAuthor":{"self":"https://jira.atlassian.com/rest/api/2/user?username=brollins","name":"brollins","emailAddress":"brollins@atlassian.com","avatarUrls":{"16x16":"https://jira.atlassian.com/secure/useravatar?size=small&avatarId=10605","48x48":"https://jira.atlassian.com/secure/useravatar?avatarId=10605" },"displayName":"Bryan Rollins [Atlassian]","active":true },"created":"2011-06-07T10:31:26.805-0500","updated":"2011-06-07T10:31:26.805-0500" },"timestamp": "2011-06-07T10:31:26.805-0500","webhookEvent": "jira:issue_updated"}
Paypal
HTTPS
webhook을 전송할 때 signature, 암호화 알고리즘, public key를 제공하여 검증하게 함
