PowerBuilder

Impossible Execution Plan

See more CURL Examples

This example demonstrates what happens when it is not possible to construct an execution plan due to missing dependencies.

The target curl command requires a {{drive_id}} value. However, no variable named drive_id has been defined, and no helper function is registered that can produce it. Although a helper function (getSite) is defined, it only produces site_id, which does not satisfy the requirement.

When ExaminePlan is called, it reports that the execution plan cannot be created because a required input is missing and no function exists to provide it.

When DoYourThing is called, it fails for the same reason. The failure is not due to a network or HTTP error, but because the dependency graph cannot be resolved. The FailReason property indicates this condition with a specific error code.

This example highlights that for an execution plan to be valid, every required input must either:

• Already have a defined value, or
• Be producible by a defined curl function with resolvable inputs

If neither condition is met, the system correctly detects the unresolved dependency and prevents execution.

PowerBuilder

integer li_rc
integer li_Success
oleobject loo_HttpCurl
string ls_TargetCurl
string ls_FnName
string ls_JsonPath
oleobject loo_JsonOAuth2
integer li_StatusCode
oleobject loo_ResponseJson

li_Success = 0

loo_HttpCurl = create oleobject
li_rc = loo_HttpCurl.ConnectToNewObject("Chilkat.HttpCurl")
if li_rc < 0 then
    destroy loo_HttpCurl
    MessageBox("Error","Connecting to COM object failed")
    return
end if

// The final curl command we want to execute.
// It depends on {{drive_id}}, which is not yet known.
ls_TargetCurl = "curl -X GET https://graph.microsoft.com/v1.0/drives/{{drive_id}}/root/children"

// Define a helper function that can produce drive_id.
// This function lists drives for a given site, which requires {{site_id}}.
ls_FnName = "getDrives"
loo_HttpCurl.AddFunction(ls_FnName,"curl -X GET https://graph.microsoft.com/v1.0/sites/{{site_id}}/drives")

// Define the output of getDrives.
// The JSON response contains an array named "value".
// We take the first element (value[0]) and extract its "id" as drive_id.
ls_JsonPath = "value[0].id"
loo_HttpCurl.AddOutput(ls_FnName,ls_JsonPath,"drive_id")

// drive_id depends on site_id, which is also not yet known.
// Define another helper function to obtain site_id.
ls_FnName = "getSite"
loo_HttpCurl.AddFunction(ls_FnName,"GET https://graph.microsoft.com/v1.0/sites/root:/sites/{{site_name}}")

// Map the "id" field from the getSite response to the variable site_id.
ls_JsonPath = "id"
loo_HttpCurl.AddOutput(ls_FnName,ls_JsonPath,"site_id")

// Provide the initial known input.
// site_name is the starting value that allows the dependency chain to be resolved.
loo_HttpCurl.SetVar("site_name","test")

// ----------------------------------------------------------------------------------------------------------------------
// Configure OAuth2 authentication using the client credentials flow.
// Secrets (client_id, client_secret, token_endpoint) are retrieved from the
// local secrets manager because EnableSecrets is enabled.
loo_JsonOAuth2 = create oleobject
li_rc = loo_JsonOAuth2.ConnectToNewObject("Chilkat.JsonObject")

loo_JsonOAuth2.EnableSecrets = 1
loo_JsonOAuth2.UpdateString("oauth2.client_id","!!sharepoint|oauth2|client_id")
loo_JsonOAuth2.UpdateString("oauth2.client_secret","!!sharepoint|oauth2|client_secret")
loo_JsonOAuth2.UpdateString("oauth2.scope","https://graph.microsoft.com/.default")
loo_JsonOAuth2.UpdateString("oauth2.token_endpoint","!!sharepoint|oauth2|token_endpoint")
loo_HttpCurl.SetAuth(loo_JsonOAuth2)
// ----------------------------------------------------------------------------------------------------------------------

// Execute the target curl command.
// Internally, the system will:
// 
// 1) Detect that {{drive_id}} is required but not defined.
// 2) Find that "getDrives" can produce drive_id.
// 3) Detect that getDrives requires {{site_id}}, which is also not defined.
// 4) Find that "getSite" can produce site_id.
// 5) Verify that getSite requires {{site_name}}, which is already known.
// 6) Build a multi-step execution plan:
//      - First:  run getSite (produces site_id)
//      - Second: run getDrives (produces drive_id)
//      - Third:  run the target curl (uses drive_id)
li_Success = loo_HttpCurl.DoYourThing(ls_TargetCurl)
if li_Success = 0 then
    Write-Debug loo_HttpCurl.LastErrorText
    destroy loo_HttpCurl
    destroy loo_JsonOAuth2
    return
end if

// Retrieve and display the HTTP response status code.
li_StatusCode = loo_HttpCurl.StatusCode
Write-Debug "response status code: " + string(li_StatusCode)

// Load and display the JSON response from the final curl command.
loo_ResponseJson = create oleobject
li_rc = loo_ResponseJson.ConnectToNewObject("Chilkat.JsonObject")

loo_ResponseJson.EmitCompact = 0
loo_HttpCurl.GetResponseJson(loo_ResponseJson)
Write-Debug loo_ResponseJson.Emit()


destroy loo_HttpCurl
destroy loo_JsonOAuth2
destroy loo_ResponseJson