(Tcl) 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.

Note: This example requires Chilkat v11.5.0 or greater.

For more information, see https://www.chilkatsoft.com/curl_dependency_engine.asp

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load ./chilkat.dll

set success 0

set httpCurl [new_CkHttpCurl]

# The target curl command requires {{order_id}}.
set targetCurl "curl -X GET https://api.example.com/orders/{{order_id}}"

# Define a helper function that produces order_id from customer_id.
set fnName "getOrderId"
CkHttpCurl_AddFunction $httpCurl $fnName "curl -X GET https://api.example.com/order-id?customer={{customer_id}}"
CkHttpCurl_AddOutput $httpCurl $fnName "order.id" "order_id"

# Define a helper function that produces customer_id from account_name.
set fnName "getCustomerId"
CkHttpCurl_AddFunction $httpCurl $fnName "curl -X GET https://api.example.com/customer-id?account={{account_name}}"
CkHttpCurl_AddOutput $httpCurl $fnName "customer.id" "customer_id"

# Provide the starting known input.
CkHttpCurl_SetVar $httpCurl "account_name" "acme"

# Examine the execution plan without running any requests.
set planJson [new_CkJsonObject]

CkJsonObject_put_EmitCompact $planJson 0

set success [CkHttpCurl_ExaminePlan $httpCurl $targetCurl $planJson]

# Success is expected to be 1.
puts "success = $success"

puts [CkJsonObject_emit $planJson]

# 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": []
#   }]
# }

delete_CkHttpCurl $httpCurl
delete_CkJsonObject $planJson