Chilkat VB.NET Upload Class Reference

Upload

Chilkat Upload is a freeware component that can be used to upload files over HTTP and HTTPS to a web server.

  • Supports both HTTP and HTTPS protocols.
  • Progress monitoring with percentage completion and "heartbeat" monitoring.
  • Abort capability.
  • Asynchronous uploads with real-time monitoring of percentage completion and number of bytes transferred.
  • Add arbitrary HTTP POST form parameters to your upload.
  • Upload multiple files in a single transaction.
  • Add arbitrary (custom) HTTP header fields to the HTTP upload.
  • Retrieve the HTTP response status, header, and body returned by the web server.

Properties

ChunkSize As Integer

The chunk size (in bytes) used by the underlying TCP/IP sockets for uploading files. The default value is 2048. This property is not typically modified.

EnableEvents As Boolean

Must be set to true to enable events. The default value is false, which prevents events from firing (and removes internal overhead associated with firing events).

HeartbeatMs As Integer

The number of milliseconds between each AbortCheck event callback. The AbortCheck callback allows an application to abort any FTP operation prior to completion. If HeartbeatMs is 0, no AbortCheck event callbacks will occur. Also, AbortCheck callbacks do not occur when doing asynchronous uploads.

Hostname As String

The hostname of the HTTP server that is the target of the upload. Do not include "http://" in the hostname. It can be a hostname, such as "www.chilkatsoft.com", or an IP address, such as "168.144.70.227".

IdleTimeoutMs As Integer

A timeout in milliseconds. The default value is 30000. If the upload hangs (i.e. progress halts) for more than this time, the component will abort the upload. (It will timeout.)

LastErrorHtml As String (ReadOnly)

Error information in HTML format for the last method called.

LastErrorText As String (ReadOnly)

Error information in plain-text format for the last method called.

LastErrorXml As String (ReadOnly)

Error information in XML format for the last method called.

Login As String

The HTTP login for sites requiring authentication. Chilkat Upload supports Basic HTTP authentication.

NumBytesSent As Integer (ReadOnly)

After an upload has completed, this property contains the number of bytes sent. During asynchronous uploads, this property contains the current number of bytes sent while the upload is in progress.

Password As String

The HTTP password for sites requiring authentication. Chilkat Upload supports Basic HTTP authentication.

Path As String

The path part of the upload URL. Some examples:

If the upload target (i.e. consumer) URL is: http://www.freeaspupload.net/freeaspupload/testUpload.asp, then

Hostname = "www.freeaspupload.net" Path = "/freeaspupload/testUpload.asp"
If the upload target URL is http://www.chilkatsoft.com/cgi-bin/ConsumeUpload.exe, then
Hostname = "www.chilkatsoft.com" Path = "/cgi-bin/ConsumeUpload.exe"

PercentUploaded As Integer (ReadOnly)

Contains the current percentage completion (0 to 100) while an asynchronous upload is in progress.

Port As Integer

The port number of the upload target (i.e. consumer) URL. The default value is 80. If SSL is used, this should be set to 443 (typically).

ProxyDomain As String

The domain name of a proxy host if an HTTP proxy is used. Do not include the "http://". The domain name may be a hostname, such as "www.chilkatsoft.com", or an IP address, such as "168.144.70.227".

HTTP Upload using a Proxy Server Example

ProxyLogin As String

If an HTTP proxy is used and it requires authentication, this property specifies the HTTP proxy login.

ProxyPassword As String

If an HTTP proxy is used and it requires authentication, this property specifies the HTTP proxy password.

ProxyPort As Integer

The port number of a proxy server if an HTTP proxy is used.

ResponseBody As Byte() (ReadOnly)

An HTTP upload is nothing more than an HTTP POST that contains the content of the files being uploaded. Just as with any HTTP POST or GET, the server should send an HTTP response that consists of header and body.

This property contains the body part of the HTTP response.

ResponseHeader As String (ReadOnly)

An HTTP upload is nothing more than an HTTP POST that contains the content of the files being uploaded. Just as with any HTTP POST or GET, the server should send an HTTP response that consists of header and body.

This property contains the header part of the HTTP response.

ResponseStatus As Integer (ReadOnly)

The HTTP response status code of the HTTP response. A list of HTTP status codes can be found here: HTTP Response Status Codes.

Ssl As Boolean

Set this to true if the upload is to HTTPS. For example, if the target of the upload is:

https://www.myuploadtarget.com/consumeUpload.asp

then set:

Ssl = true
Hostname = "www.myuploadtarget.com"
Path = "/consumeupload.asp"
Port = 443

TotalUploadSize As Integer (ReadOnly)

The total size of the upload (in bytes). This property will become set at the beginning of an asynchronous upload. A program may monitor asynchronous uploads by tracking both NumBytesSent and PercentUploaded.

This property is also set during synchronous uploads.

UploadInProgress As Boolean (ReadOnly)

Set to true when an asynchronous upload is started. When the asynchronous upload is complete, this property becomes equal to false. A program will typically begin an asynchronous upload by calling BeginUpload, and then periodically checking the value of this property to determine when the upload is complete.

UploadSuccess As Boolean (ReadOnly)

Set to true (success) or false (failed) after an asynchronous upload completes or aborts due to failure. When a program does an asynchronous upload, it will wait until UploadInProgress becomes false. It will then check the value of this property to determine if the upload was successful or not.

Version As String (ReadOnly)

The version of the Chilkat Upload component, such as "2.0.0".

Methods

Sub AbortUpload()

May be called during an asynchronous upload to abort.

Sub AddCustomHeader(ByVal name As String, ByVal value As String)

Adds a custom HTTP header to the HTTP upload.

Sub AddFileReference(ByVal name As String, ByVal filename As String)

Adds a file to the list of files to be uploaded in the next call to BlockingUpload, BeginUpload, or UploadToMemory. To upload more than one file, call this method once for each file to be uploaded.

Sub AddParam(ByVal name As String, ByVal value As String)

Adds a custom HTTP request parameter to the upload.

Function BeginUpload() As Boolean

Starts an asynchronous upload. Only one asynchronous upload may be in progress at a time. To achieve multiple asynchronous uploads, use multiple instances of the Chilkat Upload object. Each object instance is capable of managing a single asynchronous upload.

When this method is called, a background thread is started and the asynchronous upload runs in the background. The upload may be aborted at any time by calling AbortUpload. The upload is completed (or failed) when UploadInProgress becomes false. At that point, the UploadSuccess property may be checked to determine success (true) or failure (false).

Returns true for success, false for failure.

HTTP Upload with Progress Monitoring Events

Asynchronous HTTPS Upload Example

Function BlockingUpload() As Boolean

Uploads files in a synchronous manner. This method does not return until all files have been uploaded, or the upload fails. The files to be uploaded are indicated by calling AddFileReference once for each file (prior to calling this method).

Returns true for success, false for failure.

BlockingUpload Example

Function SaveLastError(ByVal filename As String) As Boolean

Saves the last error information to an XML formatted file.

Sub SleepMs(ByVal millisec As Integer)

A convenience method for putting the calling process to sleep for N milliseconds. It is provided here because some programming languages do not provide this capability, and sleeping for short increments of time is helpful when doing asynchronous uploads.

Function UploadToMemory() As Byte()

Writes the complete HTTP POST to memory. The POST contains the HTTP header, any custom params added by calling AddParam, and each file to be uploaded. This is helpful in debugging. It allows you to see the exact HTTP POST sent to the server if BlockingUpload or BeginUpload is called.

Returns Nothing on failure