GraphQL
Overview
WorkflowGen version 7.0.0 introduces the new GraphQL API, which is a modern solution to create process-driven solutions such as mobile apps, web apps, and microservices that require a powerful workflow and BPM engine.
The WorkflowGen GraphQL API is a Node.js application that runs in IIS using iisnode; it enables a high level of customization such as extending the GraphQL schema with custom types, queries or mutations, or implementing new authentication methods.
You can use GraphiQL, “a graphical interactive in-browser GraphQL IDE”, to test queries and mutations, and to browse the schema documentation.
The GraphQL API is in Alpha phase. All of the queries and mutations used by the mobile application have been implemented. The next releases will provide of the remaining User Portal and Administration Module operations.
About GraphQL
GraphQL website presentation:
“GraphQL is a query language for APIs and a runtime for fulfilling those queries with your existing data. GraphQL provides a complete and understandable description of the data in your API, gives clients the power to ask for exactly what they need and nothing more, makes it easier to evolve APIs over time, and enables powerful developer tools.”
GraphQL is a production-ready and an open source technology created by Facebook. In September 2016, Github announced its GraphQL API.
“We’ve often heard that our REST API was an inspiration for other companies; countless tutorials refer to our endpoints. Today, we’re excited to announce our biggest change to the API since we snubbed XML in favor of JSON: we’re making the GitHub API available through GraphQL.”
GraphQL is a modern API solution for React, React-Native, Angular 2, and Vue based applications.
Many GraphQL tutorials are available, it is available in many languages, and has a large community.
Technical requirements
In addition to the standard WorkflowGen installation, the following components are required:
-
IIS URL rewrite
-
Node.js LTS (version 8.11.3 for WorkflowGen version 7.11.0 and later; version 6 for earlier versions of WorkflowGen 7.x.x)
-
iisnode
For information on the installation procedure, see the WorkflowGen Technical Guide.
Endpoints
The following endpoints are available:
-
GraphQL API:
http://localhost/wfgen/graphql -
GraphiQL IDE:
http://localhost/wfgen/graphiql -
GraphQL Schema (definition language):
http://localhost/wfgen/graphql/schema
The HTTP GET method is supported on queries only. The HTTP POST method is supported on queries and mutations.
HTTP usage
Express-graphql is used to serve the GraphQL HTTP queries:
GraphQL will first look for each parameter in the URL’s query-string:
/graphql?query=query+getUser($id:ID){user(id:$id){name}}&variables={"id":"4"}
If not found in the query-string, it will look in the POST request body.
If the POST body has not yet been parsed, express-graphql will interpret it depending on the providedContent-Typeheader:
application/json: the POST body will be parsed as a JSON object of parameters.application/x-www-form-urlencoded: this POST body will be parsed as a url-encoded string of key-value pairs.application/graphql: the POST body will be parsed as GraphQL query string, which provides the query parameter.
Curl example
curl -u yourusername -X POST -H "Content-Type: application/x-www-form-urlencoded" -d 'query={
viewer {
userName
lastName
firstName
email
}
}' "http://localhost/wfgen/graphql"
And the result is:
{
"data": {
"viewer": {
"userName": "johndoe",
"lastName": "Doe",
"firstName": "John",
"email": "john.doe@acme.com"
}
}
}
Authentication
The following authentication methods are supported:
OIDC-compliant
-
Azure AD (see the WorkflowGen for Azure guide for configuration instructions)
-
AD FS 2016 (see the Active Directory Federation Services 2016 integration section in the WorkflowGen Technical Guide for configuration instructions)
-
Auth0 (see the Auth0 integration section in the WorkflowGen Technical Guide for configuration instructions)
-
Okta (see the Okta integration section in the WorkflowGen Technical Guide for configuration instructions)
-
Microsoft Identity Platform v2.0
Classic
-
IIS Basic
-
WorkflowGen authentication
-
Custom .NET authentication modules
Note: If your WorkflowGen site is configured with Integrated Windows or Basic authentication, you must configure GraphQL with Basic authentication.
HTTPS is required to secure credentials.
The GraphQL node.js app code inside the /wfgen/graphql folder can also be customized to accommodate many other authentication methods (such as oAuth 2, JWT, etc.) thanks to node libraries such as Passportjs.
User impersonation
User impersonation is supported but not recommended, and should be used only when no other technical solutions are possible. (For example, OpenID Connect-based authentication methods allow you to use access tokens to perform API operations on the client and server sides without impersonation.)
System operations allowed users can impersonate another WorkflowGen user account by setting this account’s username as the value of the x-wfgen-impersonate-username HTTP request header.
This request header can be renamed according to your naming convention. You can specify a new header name in the GraphqlImpersonateUserNameHttpHeader setting in the \wfgen\web.config file (e.g. <add key="GraphqlImpersonateUserNameHttpHeader" value="my-custom-impersonate-username" />).
To give or withdraw system operations rights to or from specific users, refer to the System operations allowed users setting in the Security section on the General tab of the Configuration Panel; alternately, you can edit the ProcessesRuntimeWebServiceAllowedUsers setting in the \wfgen\web.config file.
GraphiQL examples
You can copy/paste these queries directly in the GraphiQL IDE:
Viewer basic info (the authenticated user)
{
viewer {
userName
lastName
firstName
email
}
}
My Actions to do
{
viewer {
actions(filter: {as: ASSIGNEE, status: OPEN}}) {
totalCount
hasNextPage
hasPreviousPage
items {
request {
number
description
}
number
name
description
limit
launchUrl
}
}
}
}
Fetch a request by its number
{
request(number: 273) {
description
requester {
lastName
userName
company
}
process {
name
version
}
}
}
Create a new request
mutation {
createRequest(
input: {
processName: "PRODUCT_CREATION"
processVersion: 3
parameters: [
{
name: "CATEGORY"
type: TEXT
textValue: "robot"
direction: IN
},
{
name: "CODE"
type: TEXT
textValue: "HAL 9000"
direction: IN
},
{
name: "VALUE"
type: NUMERIC
numericValue: 600000
direction: IN
}
]
}
)
{
request {
number
followUpFormUrl
}
}
}
Global identifiers
Each GraphQL type has an id: ID! field. This ID is a global and is unique for all WorkflowGen objects.
You can use the node(id:ID!) query to retrieve a WorkflowGen object given its ID.
{
node(id: "UHJvY2VzczoxNQ==") {
id
... on Request {
number
requester {
lastName
}
}
... on Action {
limit
assignee {
id
company
}
}
... on User {
userName
email
}
}
}
Pagination
The GraphQL API supports page number based pagination. You can set a page number and a size; otherwise, the default values are:
-
1for the page number -
30for the page size
The maximum value for the page size is 100. You can change this setting in the GraphqlMaxPageSize key in the /wfgen/web.config file.
The result contains:
-
totalCount: The total number of items -
hasPreviousPage -
hasNextPage -
Items: The the list of items in the requested page.
{
viewer {
requests(page: {number: 2, size: 20}, filter: {as: REQUESTER, status: OPEN}, orderBy: {field: NUMBER, direction: DESC}) {
totalCount
hasNextPage
hasPreviousPage
items {
id
number
requester {
userName
}
}
}
}
}
To retrieve the total count without the list of items, you just need to set the page number to 0:
{
viewer {
requests(page: {number: 0}, filter: {as: REQUESTER, status: OPEN}) {
totalCount
hasNextPage
hasPreviousPage
}
}
}
Delegation management
Some GraphQL queries and mutations can be executed on behalf another user. This is possible when a user has created a delegation in WorkflowGen. The delegatee has to specify the user ID of his delegator in the onBehalfOf argument.
List of actions to do on by the delegatee on behalf of the delegator with the user ID VXNlcjoy:
{
viewer {
actions(filter: {as: ASSIGNEE, status: OPEN}, onBehalfOf:"VXNlcjoy"}) {
totalCount
hasNextPage
hasPreviousPage
items {
request {
number
description
}
number
name
description
limit
launchUrl
}
}
}
}
When the onBehalfOf argument is set, it is propagated implicitly to the all the sub-queries and fields until a User type is used.
Logs
All HTTP queries are logged by IIS as other ASP.NET web apps. Node js application logs are available in the /wfgen/graphql/iisnode/ folder. You can adjust the iisnode log file management in the /wfgen/graphql/web.config file.
Debug mode
A debug mode can be enabled by setting the GraphqlDebugEnabled key to Y in the /wfgen/web.config file.
In debug mode, some extensions are added to the GraphQL response, and additional error messages are logged in the /wfgen/graphql/iisnode/ folder.
Known limitations
actions and requests queries don’t support all argument combinations.
You must specify additional arguments (such as filter: { as: REQUESTER }).
In this example the requests and actions queries return empty lists:
{
viewer {
requests {
totalCount
hasNextPage
hasPreviousPage
}
actions {
totalCount
hasNextPage
hasPreviousPage
}
}
}