DataFlex
DataFlex
Invalidating Dependent Variables When Inputs Change
See more CURL Examples
This example demonstrates how HttpCurl automatically updates the execution plan when a known variable is cleared or changed.
After a multi-step execution plan runs successfully, variables such as site_id and drive_id may become known. Later calls to DoYourThing can reuse those values, resulting in a shorter execution plan.
However, if an input variable is cleared using ClearVar, or changed using SetVar, any variables that depend on that value are automatically invalidated. This ensures that stale values are not reused.
For example, if site_name changes, then the previously resolved site_id is no longer valid. Because drive_id depends on site_id, it is also invalidated. The next execution plan is rebuilt to resolve the dependency chain again using the new input value.
Chilkat DataFlex Downloads
Use ChilkatAx-win32.pkg
Procedure Test
Boolean iSuccess
Handle hoHttpCurl
String sTargetCurl
String sFnName
Variant vJsonOAuth2
Handle hoJsonOAuth2
Variant vPlanJson
Handle hoPlanJson
String sTemp1
Boolean bTemp1
Move False To iSuccess
Get Create (RefClass(cComChilkatHttpCurl)) To hoHttpCurl
If (Not(IsComObjectCreated(hoHttpCurl))) Begin
Send CreateComObject of hoHttpCurl
End
// The target curl command we ultimately want to execute.
// It requires drive_id.
Move "curl -X GET https://graph.microsoft.com/v1.0/drives/{{drive_id}}/root/children" To sTargetCurl
// Define a helper function that produces drive_id.
// This requires site_id.
Move "getDrives" To sFnName
Get ComAddFunction Of hoHttpCurl sFnName "curl -X GET https://graph.microsoft.com/v1.0/sites/{{site_id}}/drives" To iSuccess
Get ComAddOutput Of hoHttpCurl sFnName "value[0].id" "drive_id" To iSuccess
// Define another helper function that produces site_id.
// This requires site_name.
Move "getSite" To sFnName
Get ComAddFunction Of hoHttpCurl sFnName "curl -X GET https://graph.microsoft.com/v1.0/sites/root:/sites/{{site_name}}" To iSuccess
Get ComAddOutput Of hoHttpCurl sFnName "id" "site_id" To iSuccess
// site_name is the starting known value.
Send ComSetVar To hoHttpCurl "site_name" "test"
// Configure OAuth2 authentication.
Get Create (RefClass(cComChilkatJsonObject)) To hoJsonOAuth2
If (Not(IsComObjectCreated(hoJsonOAuth2))) Begin
Send CreateComObject of hoJsonOAuth2
End
Set ComEnableSecrets Of hoJsonOAuth2 To True
Get ComUpdateString Of hoJsonOAuth2 "oauth2.client_id" "!!sharepoint|oauth2|client_id" To iSuccess
Get ComUpdateString Of hoJsonOAuth2 "oauth2.client_secret" "!!sharepoint|oauth2|client_secret" To iSuccess
Get ComUpdateString Of hoJsonOAuth2 "oauth2.scope" "https://graph.microsoft.com/.default" To iSuccess
Get ComUpdateString Of hoJsonOAuth2 "oauth2.token_endpoint" "!!sharepoint|oauth2|token_endpoint" To iSuccess
Get pvComObject of hoJsonOAuth2 to vJsonOAuth2
Get ComSetAuth Of hoHttpCurl vJsonOAuth2 To iSuccess
// -----------------------------------------------------------------------------
// First execution plan:
// site_id and drive_id are not known yet, so the full dependency chain is needed.
// -----------------------------------------------------------------------------
Get Create (RefClass(cComChilkatJsonObject)) To hoPlanJson
If (Not(IsComObjectCreated(hoPlanJson))) Begin
Send CreateComObject of hoPlanJson
End
Set ComEmitCompact Of hoPlanJson To False
Showln "Execution plan before first call:"
Get pvComObject of hoPlanJson to vPlanJson
Get ComExaminePlan Of hoHttpCurl sTargetCurl vPlanJson To iSuccess
Get ComEmit Of hoPlanJson To sTemp1
Showln sTemp1
// Expected:
//
// {
// "plan": [{
// "function": "getSite",
// "inputs": ["site_name"],
// "outputs": ["site_id"]
// },{
// "function": "getDrives",
// "inputs": ["site_id"],
// "outputs": ["drive_id"]
// },{
// "function": "targetCurl",
// "inputs": ["drive_id"],
// "outputs": []
// }]
// }
Get ComDoYourThing Of hoHttpCurl sTargetCurl To iSuccess
If (iSuccess = False) Begin
Get ComLastErrorText Of hoHttpCurl To sTemp1
Showln sTemp1
Procedure_Return
End
Showln "After first call:"
Get ComGetVar Of hoHttpCurl "site_id" To sTemp1
Showln "site_id = " sTemp1
Get ComGetVar Of hoHttpCurl "drive_id" To sTemp1
Showln "drive_id = " sTemp1
// -----------------------------------------------------------------------------
// Second execution plan:
// site_id and drive_id are now known, so only the target curl command is needed.
// -----------------------------------------------------------------------------
Showln "Execution plan after first call:"
Get pvComObject of hoPlanJson to vPlanJson
Get ComExaminePlan Of hoHttpCurl sTargetCurl vPlanJson To iSuccess
Get ComEmit Of hoPlanJson To sTemp1
Showln sTemp1
// Expected:
//
// {
// "plan": [{
// "function": "targetCurl",
// "inputs": ["drive_id"],
// "outputs": []
// }]
// }
// -----------------------------------------------------------------------------
// Change the original input.
// Because site_id was produced from site_name, changing site_name invalidates site_id.
// Because drive_id depends on site_id, drive_id is also invalidated.
// -----------------------------------------------------------------------------
// Note: Make sure this site exists on in your SharePoint...
Send ComSetVar To hoHttpCurl "site_name" "anotherSite"
Showln "After changing site_name:"
Get ComVarDefined Of hoHttpCurl "site_id" To bTemp1
Showln "site_id defined? " bTemp1
Get ComVarDefined Of hoHttpCurl "drive_id" To bTemp1
Showln "drive_id defined? " bTemp1
// -----------------------------------------------------------------------------
// The execution plan is automatically rebuilt.
// Since site_id and drive_id were invalidated, the full dependency chain is needed again.
// -----------------------------------------------------------------------------
Showln "Execution plan after changing site_name:"
Get pvComObject of hoPlanJson to vPlanJson
Get ComExaminePlan Of hoHttpCurl sTargetCurl vPlanJson To iSuccess
Get ComEmit Of hoPlanJson To sTemp1
Showln sTemp1
// Expected:
//
// {
// "plan": [{
// "function": "getSite",
// "inputs": ["site_name"],
// "outputs": ["site_id"]
// },{
// "function": "getDrives",
// "inputs": ["site_id"],
// "outputs": ["drive_id"]
// },{
// "function": "targetCurl",
// "inputs": ["drive_id"],
// "outputs": []
// }]
// }
Get ComDoYourThing Of hoHttpCurl sTargetCurl To iSuccess
If (iSuccess = False) Begin
Get ComLastErrorText Of hoHttpCurl To sTemp1
Showln sTemp1
Procedure_Return
End
Showln "After running again with the new site_name:"
Get ComGetVar Of hoHttpCurl "site_id" To sTemp1
Showln "site_id = " sTemp1
Get ComGetVar Of hoHttpCurl "drive_id" To sTemp1
Showln "drive_id = " sTemp1
// -----------------------------------------------------------------------------
// Clearing a variable also invalidates values that depend on it.
// Here, clearing site_id also invalidates drive_id.
// -----------------------------------------------------------------------------
Send ComClearVar To hoHttpCurl "site_id"
Showln "After clearing site_id:"
Get ComVarDefined Of hoHttpCurl "site_id" To bTemp1
Showln "site_id defined? " bTemp1
Get ComVarDefined Of hoHttpCurl "drive_id" To bTemp1
Showln "drive_id defined? " bTemp1
Showln "Execution plan after clearing site_id:"
Get pvComObject of hoPlanJson to vPlanJson
Get ComExaminePlan Of hoHttpCurl sTargetCurl vPlanJson To iSuccess
Get ComEmit Of hoPlanJson To sTemp1
Showln sTemp1
// Expected:
//
// {
// "plan": [{
// "function": "getSite",
// "inputs": ["site_name"],
// "outputs": ["site_id"]
// },{
// "function": "getDrives",
// "inputs": ["site_id"],
// "outputs": ["drive_id"]
// },{
// "function": "targetCurl",
// "inputs": ["drive_id"],
// "outputs": []
// }]
// }
End_Procedure