Chaining requests in WsConnector

[marius.turiac]

Hi,

In Axelor Studio, I’m trying to set up a connector to perform a sequence of Axelor API calls. Each API call needs to use the response of the previous API call.
The documentation explains that it is possible, for example here: " The variable _1 will contain values returned from first request , so it can be used with second or subsequent requests. At the end the connector returns the result of all requests called".
My particular case (in pseudocode) is:
Request 1: GET ws/rest/…PurchaseOrder/:id
Request 2: POST /ws/action
{
« action »: « action-purchase-order-method-requested »,
« model »: « com.axelor.apps.purchase.db.PurchaseOrder »,
« data »: {
« context »: {
priceRequest=null,
notes=null,
companyExTaxTotal=994.12,
…
}
}
}
The next step will be to call the ‹ action-group-purchase-order-on-validate-actions › action in the same manner, with the same kind of payload.
My question is: how can I use the result of Request 1 and inject it in the payload of Request 2? And so on…
Requests are defined like this:

The question is what to put where the red arrow points in my screensot.
Variable _1 is available, there’s no doubt about that. The problem is that it is a Java Map object, while I have to define a json payload as depicted above.
In short, how can we use variable _1 to create the payload of Request 2 and so on?
I will really appreciate any clue.

Thank you,
Marius

[Serge.Agzr (Serge Glamazdin)]

Hi, Marius
While reproducing this case (I have similar problem to solve in my project), I have stuck with the following error:

2025-10-27 03:28:16.504 ERROR 4126 — [-26626-thread-1] org.camunda.bpm.engine.context : ENGINE-16004 Exception while closing command context: java.lang.IllegalArgumentException: org.hibernate.HibernateException: Illegal attempt to associate a collection with two open sessions. Collection : [com.axelor.apps.purchase.db.PurchaseOrder.purchaseOrderLineList#131]
com.axelor.studio.bpm.exception.AxelorScriptEngineException: java.lang.IllegalArgumentException: org.hibernate.HibernateException: Illegal attempt to associate a collection with two open sessions. Collection : [com.axelor.apps.purchase.db.PurchaseOrder.purchaseOrderLineList#131]

And still cannot find the workaround.

Regarding the paiload, here is an example (REST fetch request):

def fieldsList = ["id","partner"]
paramsMap = ["orderId" : 56, 
             "fields" : fieldsList]
def _resUpdate = __beans__.get(Class.forName('com.axelor.studio.service.ws.WsConnectorService')).callConnector(__ctx__.filterOne('WsConnector','self.name = ?1','chainPurchaseRequestConnector1').getTarget(), null, paramsMap)?.get("_1")

In your case paramsMap most likely (depends on the request) will be something like [« sourceData » : <Map_with_values>] and the key in the request payload will be - data, value - $sourceData.
P.S. It could be better not to use web requests in the scripts at all (?) and switch to the recommended by documentation method: Create requests
P.P.S. purchaseOrder is not persisted in the database until __ctx__.save(purchaseOrder) called or process came to its end, so there is nothing to pass to the next request, but __ctx__.save() call causes error:

javax.persistence.OptimisticLockException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect) : [com.axelor.apps.purchase.db.PurchaseOrder#172]

Finally it turned out to be a well known Camunda problem, here are some links: Camunda BPMN error - explanation and Camunda forum topic (asyncBefore, asyncAfter)
Hope this will help to save some time.

[Serge.Agzr (Serge Glamazdin)]

Here is the usable example of such a chain.
This process calls two connectors sequentially, one of them get Purchase Order from the database with a given id and another modifies Purchase Order note field with POST request.
Connectors and requests are defined as:

1. GET request
   

   
   
   
   

2. POST request
   

   
   
   
   
   
   
   

Process itself

Process scripts are:

1. « Purchase order is not persisted yet », type: Script

__log__.error("A.0: id - "+purchaseOrder?.id+", ver. "+purchaseOrder?.version)
// Get list of all POs to make sure it is not persisted yet
def _listOrders = __ctx__.filter(purchaseOrder.getTarget().getClass().getName(), "self.archived is null OR self.archived = false", [:])

counter = 1
for(elem : _listOrders) {
__log__.error("A."+counter+" - id = "+elem.id)
counter++
}
// Process variable for futher usage over transaction boundaries
execution.setVariable("purchaseOrderIdProcessVariable", purchaseOrder.id)
// Return something 
return purchaseOrder.typeSelect

2. « Here We Can Get Saved PO From Database With Connector and modify PO notes », type: Connector

def purchaseOrderObject = __ctx__.filterOne('PurchaseOrder', 'self.id = ?1', purchaseOrderIdProcessVariable)
// Modify and save notes field of the persisted on the transaction boundary Purchase Order
purchaseOrderObject.put('notes', purchaseOrderObject.get('notes')?:"!"+" -- some added Value")
__ctx__.save(purchaseOrderObject)

def _res = __beans__.get(Class.forName('com.axelor.studio.service.ws.WsConnectorService')).callConnector(__ctx__.filterOne('WsConnector','self.name = ?1', 'chainPurchaseRequestConnector').getTarget(), null, [orderId : purchaseOrderIdProcessVariable]).get("_1")

// Add a request result as a variable to the process context for further usage
execution.setVariable('_queryResult', _res)
execution.setVariable('purchaseOrderVersionVariable', _res.data[0].version)
__log__.error("I.3: After object update request "+_res)

3. « Here We Will also Modify PurchaseOrder notes WithConnector », type: Connector

def newNotes = (_queryResult.data[0].notes?:" ")+" (modified)"
// Prepare keys map for the POST request
def fieldsMap = ['id': purchaseOrderIdProcessVariable, 'notes': newNotes, 'version': purchaseOrderVersionVariable]
//And execute request
def _res = __beans__.get(Class.forName('com.axelor.studio.service.ws.WsConnectorService')).callConnector(__ctx__.filterOne('WsConnector','self.name = ?1', 'chainPurchaseRequestConnectorPost').getTarget(), null, fieldsMap).get("_1")
__log__.error("The end: "+_res)

Result:

1. Purchase Order notes field initially was empty, and finally, after two modifications, it is
   

   

2. Process state
   

   

3. And, the most important, here is an explanation of the Camunda transaction boundaries
   Instead of timer events you can use any other of the wait state elements.
   Useful visualizer of the Camunda transaction boundaries on the Github.

That’s all