Progress Monitoring HTTP Requests in Installed Apps

This is a note about the pitfalls of progress monitoring HTTP requests sent from an installed app (i.e. not web app running in a browser). Ideally, we’d like to know how long an HTTP POST is going to take, and update the percent-completed visually so that when it reaches 100% the operation is neatly finished as indicated.  This turns out […]

C Language Callbacks

This example demonstrates the general pattern for implementing some standard event callbacks functions for the Chilkat “C” API.  All Chilkat “classes” what have events will use the standard Chilkat events shown in the example below (AbortCheck, PercentDone, and ProgressInfo). This example demonstrates callbacks for an SFTP download, but the same technique applies to any other Chilkat “class”, such as HTTP, […]

Event Callbacks in Java

Event callbacks in Java (including Android) are supported starting in v9.5.0.52. To receive event callbacks, first create a Java class derived from one of the Chilkat event callback classes. The event callback classes are: CkBaseProgress, CkHttpProgress, CkZipProgress, CkFtp2Progress, CkMailManProgress, CkTarProgress, and CkSFtpProgress. All future Chilkat classes will only use CkBaseProgress. Theses event callback classes will be documented in the “Events” […]

“SKIP” keyword in FoxPro examples.

A helpful note from a Chilkat customer: I wanted to update you on the problem for future reference. SKIP is a reserved word in Visual Foxpro, I should have caught it, but didn’t until 2 days of screwing with it.  I knew it had to be something simple, because everything of yours worked perfect, fast, without a hitch except when […]

Delphi ActiveX Event Handling

ActiveX event callbacks can be used to get progress information for lengthy operations, especially for API calls involving communications with servers, such as FTP, SFTP (SSH), IMAP, POP3, SMTP, HTTP, etc. To use an ActiveX in Delphi, the component must be “imported”. This generates wrapper files (TLB.pas) in the “imports” directory, and may also install icons on the component palettte. […]

Cocoa Asynchronous Methods and Event Callbacks

Chilkat v9.3.0 for Cocoa now includes the asynchronous functionality and event callback functionality that has been available in the C++ libs. Asynchronous methods run in a background thread such that the call immediately returns to the application.  Events are not fired w/ asynchronous method calls — your app would periodically check to see if the background task is finished. To […]

VB6 FTP File Upload Progress Monitoring

Question: I’ve been trying to get the progress bar in VB6 to work, based on the code on your website, but I’m having no luck.  The event isn’t even being triggered. Answer: Here are some things to try: Test progress monitoring with a large enough file  such that the progress does not go from 0 to 100% instantly. Use the […]

Adding a Callback Event Handler in VB.NET

Dim “WithEvents” Dim WithEvents ftp As Chilkat.Ftp2 Add some code to create a new instance of the object. Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click ftp = New Chilkat.Ftp2() ftp.EnableEvents = True ftp.HeartbeatMs = 100 … Select the “ftp” object. Select the event. This causes Visual Studio to generate the event handler function. Add your […]

PercentDone callback counts as an AbortCheck

Question: “I’ve got the Chilkat C++ libs linked with my project, and am using the HTTP classes successfully. One thing is confusing me, though. I’ve derived a class from CkHttpProgress.h and overridden AbortCheck(…) to provide cancellation support. However, AbortCheck(…) never gets called. At first, I thought perhaps the HTTP retrieval was occurring too quickly, so I set the “HeartbeatMs” property to “1”, and it […]