HttpCurl

If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.

Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.

Possible causes of hangs include:

• A timeout property set to 0, indicating an infinite timeout.
• A hang occurring within an event callback in the application code.
• An internal bug in the Chilkat code causing the hang.

Enables variable substitution in the body of the request. The default value is True.

Set to the specific curl command in the execution plan that failed.

Set to an integer value indicating the reason for failure for the methods DoYourThing and ExaminePlan

Possible values are:

0. No error - the method succeeded or hasn't yet been called.
1. curl command syntax error.
2. HTTP response status code indidcates an authentication (401) or authorization (403) error.
3. HTTP response status code indicates an error, but not an authentication or authorization error.
4. HTTP communications failure.
5. Impossible to derive an execution plan from defined outputs and inputs.
6. A step in the execution plan did not resolve any dependency variables.
7. Failed to get curl data from a local file source (see the note below).
8. If we are within a Chilkat.Js context and don't have permission to read the local filesystem.
9. Chilkat has not been successfully unlocked by previously and successfully calling UnlockBundle.
10. Failed to open or create the local output file (if a curl option directed output to a file).

Note: curl can read data from a local file and send it in a request (usually POST/PUT) using special syntax:

• -d @file.txt → reads the file and sends it as request body (form-style encoding).
• --data-binary @file.bin → sends raw file contents exactly as-is.
• -F "file=@file.txt" → uploads the file as multipart/form-data.

The @ tells curl to load the data from a local file instead of using a literal string.

Specifies the interval, in milliseconds, between AbortCheck event callbacks.

This allows an application to periodically decide whether a long-running operation should be aborted.

The default value is 0, which means no AbortCheck callbacks are generated.

Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

Indicates the success or failure of the most recent method call: True means success, False means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages. Note: This property does not apply to methods that return integer values or to boolean-returning methods where the boolean does not indicate success or failure.

Returns the HTTP response body from the last call to DoYourThing .

Set this property to the path of a file to stream the response body to a file. If the response is streamed to a file, it will not be available in ResponseBodyStr , GetResponseSb , or GetResponseBd .

Returns the HTTP status code from the last call to DoYourThing. A value of 0 indicates no response header was received.

Provides a comma-separated list of uncommon option keywords.

This property defaults to an empty string and should normally remain empty.

If set to True, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is False. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

Version of the component/library, such as "10.1.0"

Adds a named curl function that can be used in dependency resolution. Inputs required by the curl function are indicated by the variable names enclosed in {{ and }}. Outputs are defined in one or more calls to AddOutput .

Returns True for success, False for failure.

Adds or updates a defined output for a dependency resolution curl function previously defined by calling AddFunction. The jsonPath is the JSON path in the JSON response body where the varName's value is located. If either the funcName or jsonPath already exist for the funcName, then the output is updated.

Returns True for success, False for failure.

Adds or updates an output variable definition for a dependency-resolution curl function previously created by calling AddFunction. Use this method when the curl response is JSON containing an array of objects, and a value needs to be extracted from one specific array element.

The method searches the array located at arrayPath, finds the array element where the value at wherePath matches whereValue, and then extracts the value at subPath. The extracted value is assigned to the variable named by varName.

The wherePath and subPath values are paths relative to each individual array element. The comparison between whereValue and the JSON value found at wherePath is either case-sensitive or case-insensitive depending on the value of caseSensitive.

Parameters

• funcName — The name of the curl function previously added by calling AddFunction. The output definition is associated with this function.
• arrayPath — The JSON path identifying the array of records within the JSON response.
• wherePath — A relative JSON path within each array element used to locate the matching record.
• whereValue — The value to match against the JSON value found at wherePath.
• caseSensitive — If True, the comparison between whereValue and the JSON value is case-sensitive. If False, the comparison is case-insensitive.
• subPath — A relative JSON path within the matched array element identifying the value to extract.
• varName — The name of the variable that will receive the extracted value.

Example

Given the following JSON response:

{
  "drives": [
    {
      "name": "Documents",
      "id": "A123"
    },
    {
      "name": "Shared",
      "id": "B456"
    }
  ]
}

The following call:

AddOutput2("GetDrive","drives","name","shared",false,"id","drive_id")

searches the drives array for the element whose name matches "shared" using case-insensitive comparison. The matching element is:

{
  "name": "Shared",
  "id": "B456"
}

The value of id is extracted and assigned to the variable drive_id, resulting in:

drive_id = "B456"

Returns True for success, False for failure.

Adds an automatically mapped variable for the target curl command. When a JSON response is received from a curl request, the value at the JSON path specified by jsonPath is extracted (if present) and assigned to the variable named by varName.

This is useful in common workflows where one request returns an identifier (such as an `id`) that must be reused in a subsequent curl request.

Returns True for success, False for failure.

Clears (undefines) the target output for the specified varName. If varName equals "*", then all target outputs are cleared.

Undefines the variable with the specified name. If varName equals "*", then all variables are cleared.

Returns True for success, False for failure.

Runs a the targetCurl command specified in targetCurl. If the targetCurl contains variable names enclosed in {{ and }}, then an execution plan is constructed from defined functions and outputs to resolve unknown variables, and the execution plan is run. The final step in the execution plan is always the targetCurl command.

Returns success (True) if a response was received, in which case the response status code will be available in StatusCode and the content of the response body will be available in one of two places:

• If ResponseFilePath is non-empty, the response body was streamed to the specified file path.
• If ResponseFilePath is empty, the response body can be retrieved via ResponseBodyStr , GetResponseSb , or GetResponseBd . Binary responses should only be retrieved via ResponseBodyBd .

Assuming the HTTP response is JSON, the target outputs (variables) specified by prior calls to AddTargetOutput will be populated by applying each variable's JSON path to the response JSON.

Returns True for success, False for failure.

Used for debugging. Returns in json the plan of execution that would occur for the curl based on the variables that are either unknown or already known. The plan of execution is what would occur if DoYourThing was called with the current state of knowledge.

If no execution plan is possible with the current known inputs and outputs, then json provides information about what is missing and the method returns False.

Returns True for success, False for failure.

Returns all defined variables in json.

Appends to bd the HTTP response body from the last call to DoYourThing.

Returns True for success, False for failure.

Writes to jarr the HTTP response body from the last call to DoYourThing.

Returns True for success, False for failure.

Writes to json the HTTP response body from the last call to DoYourThing.

Returns True for success, False for failure.

Appends to sb the HTTP response body from the last call to DoYourThing.

Returns True for success, False for failure.

Writes to xml the HTTP response body from the last call to DoYourThing.

Returns True for success, False for failure.

Retrieves the current value of the variable specified by varName.

Returns True for success, False for failure.

Sets authorization information that is applied to all calls to DoYourThing . See the examples below for details.

Returns True for success, False for failure.

Sets the value of a variable to be replaced in curl commands. Variable names are enclosed in {{ and }} and can occur in the path, query params, or the body of the request.

Returns True for success, False for failure.

Used for debugging purposes. This method behaves the same as DoYourThing , but only converts the curlCommand to an HTTP request message in sb containing the full structure:

• start line
• headers
• optional body or multipart body

It does not actually send the HTTP request.

Returns True for success, False for failure.

Returns True if the varName is defined, otherwise returns False. Setting varName to "!" checks whether all target output variables have been defined. It returns True if every target output is set, and False if any are missing.

Enables a method call to be aborted by triggering the AbortCheck event at intervals defined by the HeartbeatMs property. If HeartbeatMs is set to its default value of 0, no events will occur. For instance, set HeartbeatMs to 200 to trigger 5 AbortCheck events per second.

Event callback implementation:

// A handler is a method of one of your own classes, e.g. a form:
function TMyObject.HttpCurlAbortCheck(Sender: TChilkatBase): Boolean;
begin
  // Called every HeartbeatMs milliseconds while a method is running.
  // Return True to abort the method; return False to continue.
  Result := False;
end;

To add an event handler:

httpcurl := THttpCurl.Create;
httpcurl.HeartbeatMs := 250;   // fire OnAbortCheck 4 times per second
httpcurl.OnAbortCheck := MyObject.HttpCurlAbortCheck;

This provides the percentage completion for any method involving network communications or time-consuming processing, assuming the progress can be measured as a percentage. This event is triggered only when it's possible and logical to express the operation's progress as a percentage. The pctDone argument will range from 1 to 100. For methods that finish quickly, the number of PercentDone callbacks may vary, but the final callback will have pctDone equal to 100. For longer operations, callbacks will not exceed one per percentage point (e.g., 1, 2, 3, ..., 98, 99, 100).

The PercentDone callback also acts as an AbortCheck event. For fast methods where PercentDone fires, an AbortCheck event may not trigger since the PercentDone callback already provides an opportunity to abort. For longer operations, where time between PercentDone callbacks is extended, AbortCheck callbacks enable more responsive operation termination.

To abort the operation, set the abort output argument to True. This will cause the method to terminate and return a failure status or corresponding failure value.

Event callback implementation:

// A handler is a method of one of your own classes, e.g. a form:
function TMyObject.HttpCurlPercentDone(Sender: TChilkatBase; PctDone: Integer): Boolean;
begin
  // PctDone ranges from 1 to 100.
  WriteLn('Percent done: ', PctDone);
  // Return True to abort the method; return False to continue.
  Result := False;
end;

To add an event handler:

httpcurl := THttpCurl.Create;
httpcurl.OnPercentDone := MyObject.HttpCurlPercentDone;

This event callback provides tag name/value pairs that detail what occurs during a method call. To discover existing tag names, create code to handle the event, emit the pairs, and review them. Most tag names are self-explanatory.

Note: Some Chilkat methods don't fire any ProgressInfo events.

Event callback implementation:

// A handler is a method of one of your own classes, e.g. a form:
procedure TMyObject.HttpCurlProgressInfo(Sender: TChilkatBase; const Name, Value: string);
begin
  WriteLn(Name, ': ', Value);
end;

To add an event handler:

httpcurl := THttpCurl.Create;
httpcurl.OnProgressInfo := MyObject.HttpCurlProgressInfo;