TChilkatHttpRequest Delphi ActiveX Reference Documentation

TChilkatHttpRequest

Current Version: 9.5.0.97

Represents a complete HTTP request.

Importing the Chilkat ActiveX into Delphi

Important: When upgrading to a new version of Chilkat, make sure to re-imported ActiveX DLL into Delphi to regenerate the files described below.

Two things are required to use an ActiveX in Delphi:

  1. The ActiveX DLL needs to be registered via regsvr32 on the system where the Delphi application runs. See How To Register ActiveX DLLs for detailed information.
  2. See also: ActiveX Registration Tutorial
  3. The ActiveX component needs to be "imported". Use the Delphi Import Component Wizard to import the Chilkat type library. This creates the following files: Chilkat_v9_5_0_TLB.pas and Chilkat_v9_5_0_TLB.dcr. The Chilkat_v9_5_0_TLB.pas should be added to your project.

To import the Chilkat type library, do the following:

  1. In the Delphi RAD Studio, select the menu item "Component" --> "Import a Type Library".
  2. Find "Chilkat ActiveX v9.5.0" in the list and select it. This will only appear in the list if the ChilkatAx-9.5.0-win32.dll (or ChilkatAx-9.5.0-x64.dll) has been registered w/ regsvr32.
  3. Check the "Generate Component Wrappers" checkbox.
  4. Select a directory where the unit files (.pas and .dcr) should be generated.
  5. Select "Create Unit" and then "Finish".
  6. Add the .pas to your Delphi project.

To use a Chilkat ActiveX object in your Delphi code, add "Chilkat_v9_5_0_TLB" to the "uses" statement. For example:

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_v9_5_0_TLB;

Object Creation

var
obj: TChilkatHttpRequest;
...
begin
obj := TChilkatHttpRequest.Create(Self);
...
// When finished, free the object instance.
obj.Free();

Properties

Boundary
property Boundary: WideString
Introduced in version 9.5.0.49

Sets an explicit boundary string to be used in multipart/form-data requests. If no Boundary is set, then a boundary string is automaticaly generated as needed during the sending of a request.

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Charset
property Charset: WideString

Controls the character encoding used for HTTP request parameters for POST requests. The default value is the ANSI charset of the computer. The charset should match the charset expected by the form target.

The "charset" attribute is only included in the Content-Type header of the request if the SendCharset property is set to 1.

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ContentType
property ContentType: WideString

The ContentType property sets the "Content-Type" header field, and identifies the content-type of the HTTP request body. Common values are:

application/x-www-form-urlencoded
multipart/form-data
application/json
application/xml
If ContentType is set equal to the empty string, then no Content-Type header is included in the HTTP request.

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DebugLogFilePath
property DebugLogFilePath: WideString

If set to a file path, causes each Chilkat method or property call to automatically append it's LastErrorText to the specified log file. The information is appended such that if a hang or crash occurs, it is possible to see the context in which the problem occurred, as well as a history of all Chilkat calls up to the point of the problem. The VerboseLogging property can be set to provide more detailed information.

This property is typically used for debugging the rare cases where a Chilkat method call hangs or generates an exception that halts program execution (i.e. crashes). A hang or crash should generally never happen. The typical causes of a hang are:

  1. a timeout related property was set to 0 to explicitly indicate that an infinite timeout is desired,
  2. the hang is actually a hang within an event callback (i.e. it is a hang within the application code), or
  3. there is an internal problem (bug) in the Chilkat code that causes the hang.

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EntireHeader
property EntireHeader: WideString

Composes and returns the entire MIME header of the HTTP request.

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HttpVerb
property HttpVerb: WideString

The HttpVerb property should be set to the name of the HTTP method that appears on the "start line" of an HTTP request, such as GET, POST, PUT, DELETE, etc. It is also possible to use the various WebDav verbs such as PROPFIND, PROPPATCH, MKCOL, COPY, MOVE, LOCK, UNLOCK, etc. In general, the HttpVerb may be set to anything, even custom verbs recognized by a custom server-side app.

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HttpVersion
property HttpVersion: WideString

The HTTP version in the request header. Defaults to "1.1".

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LastBinaryResult
property LastBinaryResult: OleVariant readonly

The binary data returned by the last (binary data returning) method called. Only available if Chilkat.Global.KeepBinaryResult is set to 1. This provides a means for obtaining large varbinary results in the SQL Server environment (where limitations exist in getting large amounts of data returned by method calls, but where temp tables can be used for binary properties).

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LastErrorHtml
property LastErrorHtml: WideString readonly

Provides information in HTML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastErrorText
property LastErrorText: WideString readonly

Provides information in plain-text format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastErrorXml
property LastErrorXml: WideString readonly

Provides information in XML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastMethodSuccess
property LastMethodSuccess: Integer

Indicate whether the last method call succeeded or failed. A value of 1 indicates success, a value of 0 indicates failure. This property is automatically set for method calls. It is not modified by property accesses. The property is automatically set to indicate success for the following types of method calls:

  • Any method that returns a string.
  • Any method returning a Chilkat object, binary bytes, or a date/time.
  • Any method returning a standard boolean status value where success = 1 and failure = 0.
  • Any method returning an integer where failure is defined by a return value less than zero.

Note: Methods that do not fit the above requirements will always set this property equal to 1. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.

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LastStringResult
property LastStringResult: WideString readonly

The string return value of the last (string returning) method called. Only available if Chilkat.Global.KeepStringResult is set to 1. This provides a means for obtaining large string results in the SQL Server environment (where limitations exist in getting long strings returned by method calls, but where temp tables can be used for string properties).

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LastStringResultLen
property LastStringResultLen: Integer readonly

The length, in characters, of the string contained in the LastStringResult property.

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NumHeaderFields
property NumHeaderFields: Integer readonly

Returns the number of request header fields.

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NumParams
property NumParams: Integer readonly

Returns the number of query parameters.

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Path
property Path: WideString

The path of the resource requested. A path of "/" indicates the default document of a domain.

Explaining the Parts of a URL

http://example.com:8042/over/there?name=ferret#nose
\__/   \______________/\_________/ \________/ \__/
 |           |            |            |        |
scheme   domain+port     path        query   fragment

This property should be set to the path part of the URL. You may also include the query part in this property value. If the Content-Type of the request is NOT application/x-www-form-urlencoded, then you would definitely want to include query parameters in the path. If the Content-Type of the request IS application/x-www-form-urlencoded, the query parameters are passed in the body of the request. It is also possible to pass some query parameters via the path, and some in the body of a application/x-www-form-urlencoded request, but you shouldn't include the same parameter in both places. You would never need to include the fragment part. The fragment is nothing more than an instruction for a browser to automatically navigate to a particular location in the HTML page (assuming the request returns HTML, otherwise a fragment makes no sense).

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SendCharset
property SendCharset: Integer

Controls whether the charset is explicitly included in the content-type header field of the HTTP POST request. The default value of this property is 0.

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VerboseLogging
property VerboseLogging: Integer

If set to 1, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is 0. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

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Version
property Version: WideString readonly

Version of the component/library, such as "9.5.0.94"

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Methods

AddBdForUpload
function AddBdForUpload(name: WideString; remoteFilename: WideString; byteData: TChilkatBinData; contentType: WideString): Integer;
Introduced in version 9.5.0.76

Adds a file to an upload request where the contents of the file come from byteData.

name is an arbitrary name. (In HTML, it is the form field name of the input tag.)
remoteFilename is the name of the file to be created on the HTTP server.
byteData contains the bytes to be uploaded.
contentType contains is the value of the Content-Type header. An empty string may be passed to allow Chilkat to automatically determine the Content-Type based on the filename extension.

Returns 1 for success, 0 for failure.

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AddBytesForUpload
function AddBytesForUpload(name: WideString; remoteFileName: WideString; byteData: OleVariant): Integer;

Adds a file to an upload request where the contents of the file come from an in-memory byte array. To create a file upload request, set the ContentType property = "multipart/form-data" and then call AddBytesForUpload, AddStringForUpload, or AddFileForUpload for each file to be uploaded.

name is an arbitrary name. (In HTML, it is the form field name of the input tag.)
remoteFileName is the name of the file to be created on the HTTP server.
byteData contains the contents (bytes) to be uploaded.

Returns 1 for success, 0 for failure.

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AddBytesForUpload2
function AddBytesForUpload2(name: WideString; remoteFileName: WideString; byteData: OleVariant; contentType: WideString): Integer;

Same as AddBytesForUpload, but allows the Content-Type header field to be directly specified. (Otherwise, the Content-Type header is automatically determined based on the remoteFileName's file extension.)

Returns 1 for success, 0 for failure.

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AddFileForUpload
function AddFileForUpload(name: WideString; filePath: WideString): Integer;

Adds a file to an upload request. To create a file upload request, set the ContentType property = "multipart/form-data" and then call AddFileForUpload, AddBytesForUpload, or AddStringForUpload for each file to be uploaded. This method does not read the file into memory. When the upload occurs, the data is streamed directly from the file, thus allowing for very large files to be uploaded without consuming large amounts of memory.

name is an arbitrary name. (In HTML, it is the form field name of the input tag.)
filePath is the path to an existing file in the local filesystem.

Returns 1 for success, 0 for failure.

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AddFileForUpload2
function AddFileForUpload2(name: WideString; filePath: WideString; contentType: WideString): Integer;

Same as AddFileForUpload, but allows the Content-Type header field to be directly specified. (Otherwise, the Content-Type header is automatically determined based on the file extension.)

name is an arbitrary name. (In HTML, it is the form field name of the input tag.)
filePath is the path to an existing file in the local filesystem.

Returns 1 for success, 0 for failure.

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AddHeader
procedure AddHeader(name: WideString; value: WideString);

Adds a request header to the HTTP request. If a header having the same field name is already present, this method replaces it.

Note: Never explicitly set the Content-Length header field. Chilkat will automatically compute the correct length and add the Content-Length header to all POST, PUT, or any other request where the Content-Length needs to be specified. (GET requests always have a 0 length body, and therefore never need a Content-Length header field.)

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AddMwsSignature
function AddMwsSignature(domain: WideString; mwsSecretKey: WideString): Integer;
Introduced in version 9.5.0.66

Computes the Amazon MWS signature using the mwsSecretKey and adds the "Signature" parameter to the request. This method should be called for all Amazon Marketplace Web Service (Amazon MWS) HTTP requests. It should be called after all request parameters have been added.

Important: The Chilkat v9.5.0.75 release accidentally breaks Amazon MWS (not AWS) authentication. If you need MWS with 9.5.0.75, send email to support@chilkatsoft.com for a hotfix, or revert back to v9.5.0.73, or update to a version after 9.5.0.75.

The domain should be the domain of the request, such as one of the following:

  • mws.amazonservices.com
  • mws-eu.amazonservices.com
  • mws.amazonservices.in
  • mws.amazonservices.com.cn
  • mws.amazonservices.jp

Note: This method automatically adds or replaces the existing Timestamp parameter to the current system date/time.

Returns 1 for success, 0 for failure.

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AddParam
procedure AddParam(name: WideString; value: WideString);

Adds a request query parameter (name/value pair) to the HTTP request. The name and value strings passed to this method should not be URL encoded.

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AddStringForUpload
function AddStringForUpload(name: WideString; filename: WideString; strData: WideString; charset: WideString): Integer;

Same as AddFileForUpload, but the upload data comes from an in-memory string instead of a file.

Returns 1 for success, 0 for failure.

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AddStringForUpload2
function AddStringForUpload2(name: WideString; filename: WideString; strData: WideString; charset: WideString; contentType: WideString): Integer;

Same as AddStringForUpload, but allows the Content-Type header field to be directly specified. (Otherwise, the Content-Type header is automatically determined based on the filename's file extension.)

Returns 1 for success, 0 for failure.

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AddSubHeader
function AddSubHeader(index: Integer; name: WideString; value: WideString): Integer;
Introduced in version 9.5.0.55

Adds a request header to the Nth sub-header of the HTTP request. If a header having the same field name is already present, this method replaces it.

Returns 1 for success, 0 for failure.

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GenerateRequestFile
function GenerateRequestFile(path: WideString): Integer;
Introduced in version 9.5.0.64

The same as GenerateRequestText, except the generated request is written to the file specified by path.

Returns 1 for success, 0 for failure.

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GenerateRequestText
function GenerateRequestText(): WideString;

Returns the request text that would be sent if Http.SynchronousRequest was called.

Returns a zero-length WideString on failure

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GetHeaderField
function GetHeaderField(name: WideString): WideString;

Returns the value of a request header field.

Returns a zero-length WideString on failure

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GetHeaderName
function GetHeaderName(index: Integer): WideString;

Returns the Nth request header field name. Indexing begins at 0, and the number of request header fields is specified by the NumHeaderFields property.

Returns a zero-length WideString on failure

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GetHeaderValue
function GetHeaderValue(index: Integer): WideString;

Returns the Nth request header field value. Indexing begins at 0, and the number of request header fields is specified by the NumHeaderFields property.

Returns a zero-length WideString on failure

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GetParam
function GetParam(name: WideString): WideString;

Returns a request query parameter value by name.

Returns a zero-length WideString on failure

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GetParamName
function GetParamName(index: Integer): WideString;

Returns the Nth request query parameter field name. Indexing begins at 0, and the number of request query parameter fields is specified by the NumParams property.

Returns a zero-length WideString on failure

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GetParamValue
function GetParamValue(index: Integer): WideString;

Returns the Nth request query parameter field value. Indexing begins at 0, and the number of request query parameter fields is specified by the NumParams property.

Returns a zero-length WideString on failure

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GetUrlEncodedParams
function GetUrlEncodedParams(): WideString;

Returns the request parameters in URL encoded form (i.e. in the exact form that would be sent if the ContentType property was application/x-www-form-urlencoded). For example, if a request has two params: param1="abc 123" and param2="abc-123", then GetUrlEncodedParams would return "abc+123&param2=abc%2D123"

Returns a zero-length WideString on failure

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LoadBodyFromBd
function LoadBodyFromBd(requestBody: TChilkatBinData): Integer;
Introduced in version 9.5.0.67

Uses the contents of the requestBody as the HTTP request body.

Returns 1 for success, 0 for failure.

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LoadBodyFromBytes
function LoadBodyFromBytes(byteData: OleVariant): Integer;

The HTTP protocol is such that all HTTP requests are MIME. For non-multipart requests, this method may be called to set the MIME body of the HTTP request to the exact contents of the byteData.
Note: A non-multipart HTTP request consists of (1) the HTTP start line, (2) MIME header fields, and (3) the MIME body. This method sets the MIME body.

Returns 1 for success, 0 for failure.

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LoadBodyFromFile
function LoadBodyFromFile(filePath: WideString): Integer;

The HTTP protocol is such that all HTTP requests are MIME. For non-multipart requests, this method may be called to set the MIME body of the HTTP request to the exact contents of filePath.
Note: A non-multipart HTTP request consists of (1) the HTTP start line, (2) MIME header fields, and (3) the MIME body. This method sets the MIME body.

Returns 1 for success, 0 for failure.

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LoadBodyFromSb
function LoadBodyFromSb(requestBody: TChilkatStringBuilder; charset: WideString): Integer;
Introduced in version 9.5.0.67

Uses the contents of the requestBody as the HTTP request body. The charset indicates the binary representation of the string, such as "utf-8", "utf-16", "iso-8859-*", "windows-125*", etc. Any of the character encodings supported at the link below are valid.

Returns 1 for success, 0 for failure.

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LoadBodyFromString
function LoadBodyFromString(bodyStr: WideString; charset: WideString): Integer;

The HTTP protocol is such that all HTTP requests are MIME. For non-multipart requests, this method may be called to set the MIME body of the HTTP request to the exact contents of bodyStr.
Note: A non-multipart HTTP request consists of (1) the HTTP start line, (2) MIME header fields, and (3) the MIME body. This method sets the MIME body.

charset indicates the charset, such as "utf-8" or "iso-8859-1", to be used. The HTTP body will contain the bodyStr converted to this character encoding.

Returns 1 for success, 0 for failure.

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RemoveAllParams
procedure RemoveAllParams();

Removes all request parameters.

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RemoveHeader
function RemoveHeader(name: WideString): Integer;

Removes all occurrences of a HTTP request header field. Always returns 1.

Returns 1 for success, 0 for failure.

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RemoveParam
procedure RemoveParam(name: WideString);

Removes a single HTTP request parameter by name.

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SetFromUrl
procedure SetFromUrl(url: WideString);

Parses a URL and sets the Path and query parameters (NumParams, GetParam, GetParamName, GetParamValue).

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StreamBodyFromFile
function StreamBodyFromFile(filePath: WideString): Integer;

Useful for sending HTTP requests where the body is a very large file. For example, to send an XML HttpRequest containing a very large XML document, one would set the HttpVerb = "POST", the ContentType = "text/xml", and then call StreamBodyFromFile to indicate that the XML body of the request is to be streamed directly from a file. When the HTTP request is actually sent, the body is streamed directly from the file, and thus the file never needs to be loaded in its entirety in memory.

Returns 1 for success, 0 for failure.

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StreamChunkFromFile
function StreamChunkFromFile(path: WideString; offset: WideString; numBytes: WideString): Integer;
Introduced in version 9.5.0.55

This method is the same as StreamBodyFromFile, but allows for an offset and number of bytes to be specified. The offset and numBytes are integers passed as strings.

Returns 1 for success, 0 for failure.

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