(Visual Basic 6.0) curl with Target Outputs

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For curl requests that return JSON, you can define output variables that extract specific values directly from the response. Instead of manually parsing the JSON, you provide a JSON path for each value you want. Chilkat uses this path to locate the value and assign it to a variable, which your application can then retrieve using GetVar.

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

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Dim success As Long
success = 0

' This example executes a curl command to retrieve information about a SharePoint site
' from Microsoft Graph. The request uses variable placeholders that will be replaced
' at runtime with actual values.
' 
' Equivalent curl command:
' 
' curl -X GET "https://graph.microsoft.com/v1.0/sites/{{sharepoint_hostname}}:/sites/{{site_name}}" \
'   -H "Authorization: Bearer ACCESS_TOKEN" \
'   -H "Accept: application/json"
' 
' A typical JSON response looks like this:
' 
' {
'   "@odata.context": "...",
'   "createdDateTime": "...",
'   "description": "Test site",
'   "id": "example.sharepoint.com,...",
'   "lastModifiedDateTime": "...",
'   "name": "test",
'   "webUrl": "...",
'   "displayName": "test",
'   "root": {},
'   "siteCollection": {
'     "hostname": "example.sharepoint.com"
'   }
' }
' 
' Rather than processing the entire JSON response, this example extracts only the
' specific values we care about: id, description, and siteCollection.hostname.
' These values are located at known JSON paths, so we can define them as "target outputs".

Dim sbTargetCurl As New ChilkatStringBuilder
success = sbTargetCurl.AppendLn("curl -X GET ""https://graph.microsoft.com/v1.0/sites/{{sharepoint_hostname}}:/sites/{{site_name}}"" \")
success = sbTargetCurl.AppendLn("  -H ""Authorization: Bearer ACCESS_TOKEN"" \")
success = sbTargetCurl.AppendLn("  -H ""Accept: application/json""")

Dim httpCurl As New ChilkatHttpCurl

' 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 set to true.
Dim jsonOAuth2 As New ChilkatJsonObject
jsonOAuth2.EnableSecrets = 1
success = jsonOAuth2.UpdateString("oauth2.client_id","!!sharepoint|oauth2|client_id")
success = jsonOAuth2.UpdateString("oauth2.client_secret","!!sharepoint|oauth2|client_secret")
success = jsonOAuth2.UpdateString("oauth2.scope","https://graph.microsoft.com/.default")
success = jsonOAuth2.UpdateString("oauth2.token_endpoint","!!sharepoint|oauth2|token_endpoint")
success = httpCurl.SetAuth(jsonOAuth2)

' Define values for the variables used in the curl command.
' These replace the {{sharepoint_hostname}} and {{site_name}} placeholders at runtime.
httpCurl.SetVar "sharepoint_hostname","example.sharepoint.com"
httpCurl.SetVar "site_name","test"

' Define target outputs for the curl command.
' Each call maps a JSON path in the response to a variable name.
' After execution, these variables can be retrieved using GetVar.
httpCurl.AddTargetOutput "id","site_id"
httpCurl.AddTargetOutput "description","site_description"
httpCurl.AddTargetOutput "siteCollection.hostname","site_hostname"

' Execute the curl command. Variable substitution and authentication
' are handled automatically.
success = httpCurl.DoYourThing(sbTargetCurl.GetAsString())
If (success = 0) Then
    Debug.Print httpCurl.LastErrorText
    Exit Sub
End If

' Load the JSON response from the server.
Dim responseJson As New ChilkatJsonObject
responseJson.EmitCompact = 0
success = httpCurl.GetResponseJson(responseJson)

' Check the HTTP status code returned by the request.
Dim statusCode As Long
statusCode = httpCurl.StatusCode
Debug.Print "response status code: " & statusCode

If (statusCode <> 200) Then
    ' If the request failed, the JSON response will contain error details
    ' instead of the expected data.
    Debug.Print responseJson.Emit()
    Exit Sub
End If

' Verify that all target output variables were successfully extracted.
' Passing "!" to VarDefined returns 1 only if all target outputs are defined.
Dim allTargetsDefined As Long
allTargetsDefined = httpCurl.VarDefined("!")
If (allTargetsDefined = 0) Then
    Debug.Print httpCurl.LastErrorText
    Debug.Print "Not all target outputs were located and defined."
    Exit Sub
End If

' Retrieve and display the extracted values from the response.
Debug.Print "site_id = " & httpCurl.GetVar("site_id")
Debug.Print "site_description = " & httpCurl.GetVar("site_description")
Debug.Print "site_hostname = " & httpCurl.GetVar("site_hostname")

' Example output:

' site_id = example.sharepoint.com,9b923c5e-5117-44ad-8b03-cdbb8e19ae85,b2451e19-290f-4f29-9f5d-674c2951a9f7
' site_description = Test site
' site_hostname = example.sharepoint.com