B4X Requires Chilkat v11.5.0+

curl with Target Outputs

See more CURL Examples

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. B4X

Dim success As Boolean = False

'  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 ChilkatStringBuilder
sbTargetCurl.Initialize
sbTargetCurl.AppendLn("curl -X GET " & Chr(34) & "https://graph.microsoft.com/v1.0/sites/{{sharepoint_hostname}}:/sites/{{site_name}}" & Chr(34) & " \")
sbTargetCurl.AppendLn("  -H " & Chr(34) & "Authorization: Bearer ACCESS_TOKEN" & Chr(34) & " \")
sbTargetCurl.AppendLn("  -H " & Chr(34) & "Accept: application/json" & Chr(34))

Dim httpCurl As ChilkatHttpCurl
httpCurl.Initialize("httpCurl")

'  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 ChilkatJsonObject
jsonOAuth2.Initialize
jsonOAuth2.EnableSecrets = True
jsonOAuth2.UpdateString("oauth2.client_id", "!!sharepoint|oauth2|client_id")
jsonOAuth2.UpdateString("oauth2.client_secret", "!!sharepoint|oauth2|client_secret")
jsonOAuth2.UpdateString("oauth2.scope", "https://graph.microsoft.com/.default")
jsonOAuth2.UpdateString("oauth2.token_endpoint", "!!sharepoint|oauth2|token_endpoint")
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 = False Then
    Log(httpCurl.LastErrorText)
    Return
End If


'  Load the JSON response from the server.
Dim responseJson As ChilkatJsonObject
responseJson.Initialize
responseJson.EmitCompact = False
httpCurl.GetResponseJson(responseJson)

'  Check the HTTP status code returned by the request.
Dim statusCode As Int = httpCurl.StatusCode
Log("response status code: " & statusCode)

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


'  Verify that all target output variables were successfully extracted.
'  Passing "!" to VarDefined returns True only if all target outputs are defined.
Dim allTargetsDefined As Boolean = httpCurl.VarDefined("!")
If allTargetsDefined = False Then
    Log(httpCurl.LastErrorText)
    Log("Not all target outputs were located and defined.")
    Return
End If


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