Visual Basic 6.0

Viewing a Simple Three-Step Execution Plan

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This example demonstrates a straightforward, valid dependency chain that results in a three-step execution plan. The goal is not to execute the requests, but to inspect how the plan is constructed using ExaminePlan.

The target curl command requires {{order_id}}. A helper function is defined to produce order_id, but it depends on customer_id. Another helper function produces customer_id, which depends on account_name.

Because account_name is provided as a known input, the dependency chain can be fully resolved:

• customer_id is obtained from account_name
• order_id is obtained from customer_id
• The target curl command uses order_id

When ExaminePlan is called, it builds and returns a three-step execution plan showing the order in which each function would be executed.

Visual Basic 6.0

Dim success As Long
success = 0

Dim httpCurl As New ChilkatHttpCurl

' The target curl command requires {{order_id}}.
Dim targetCurl As String
targetCurl = "curl -X GET https://api.example.com/orders/{{order_id}}"

' Define a helper function that produces order_id from customer_id.
Dim fnName As String
fnName = "getOrderId"
success = httpCurl.AddFunction(fnName,"curl -X GET https://api.example.com/order-id?customer={{customer_id}}")
success = httpCurl.AddOutput(fnName,"order.id","order_id")

' Define a helper function that produces customer_id from account_name.
fnName = "getCustomerId"
success = httpCurl.AddFunction(fnName,"curl -X GET https://api.example.com/customer-id?account={{account_name}}")
success = httpCurl.AddOutput(fnName,"customer.id","customer_id")

' Provide the starting known input.
httpCurl.SetVar "account_name","acme"

' Examine the execution plan without running any requests.
Dim planJson As New ChilkatJsonObject
planJson.EmitCompact = 0

success = httpCurl.ExaminePlan(targetCurl,planJson)

' Success is expected to be 1.
Debug.Print "success = " & success

Debug.Print planJson.Emit()

' Expected result:
' 
' {
'   "plan": [{
'     "function": "getCustomerId",
'     "inputs": ["account_name"],
'     "outputs": ["customer_id"]
'   },{
'     "function": "getOrderId",
'     "inputs": ["customer_id"],
'     "outputs": ["order_id"]
'   },{
'     "function": "targetCurl",
'     "inputs": ["order_id"],
'     "outputs": []
'   }]
' }