I want to make a file downloader, but it keeps encountering issues.

[zzzzzzz7]

You like the teacher, I want to make a downloader, but when running inward, it always crashes into the main network base address like @Self before, and it's quite aggressive.

[Handoko]

You can study from these examples:
https://forum.lazarus.freepascal.org/index.php/topic,42929.msg299868.html#msg299868
https://forum.lazarus.freepascal.org/index.php/topic,53601.msg398932.html#msg398932
https://forum.lazarus.freepascal.org/index.php/topic,43166.msg301678.html#msg301678
https://forum.lazarus.freepascal.org/index.php/topic,67442.msg519185.html#msg519185

[zzzzzzz7]

You can study from these examples:
https://forum.lazarus.freepascal.org/index.php/topic,42929.msg299868.html#msg299868
https://forum.lazarus.freepascal.org/index.php/topic,53601.msg398932.html#msg398932
https://forum.lazarus.freepascal.org/index.php/topic,43166.msg301678.html#msg301678
https://forum.lazarus.freepascal.org/index.php/topic,67442.msg519185.html#msg519185

thank you ，But I don't understand. Can you give me the simplest substitute?

[rvk]

thank you ，But I don't understand. Can you give me the simplest substitute?

You didn't show anything from your code so how can we show a simple substitute?

[jamie]

thank you ，But I don't understand. Can you give me the simplest substitute?

You didn't show anything from your code so how can we show a simple substitute?

Aren't you a mind reader, lost your magic wand?

Jamie

[Aruna]

You like the teacher, I want to make a downloader, but when running inward, it always crashes into the main network base address like @Self before, and it's quite aggressive.

The code below has been tested and works on Linux. Your mileage may vary  :) You must give it the full path including file name to be saved else will choke.

EDIT: The attached ZIP is for you to test and explore.

Code: Pascal  [Select][+][-]

1. unit Unit1;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils, Forms, Controls, Graphics, Dialogs, StdCtrls,
9.   fphttpclient, opensslsockets;
10.  
11.  
12. type
13.  
14.   { TForm1 }
15.  
16.   TForm1 = class(TForm)
17.     Button1: TButton;
18.     Edit1: TEdit;
19.     procedure Button1Click(Sender: TObject);
20.   private
21.  
22.   public
23.  
24.   end;
25.  
26. var
27.   Form1: TForm1;
28.  
29. implementation
30.  
31. {$R *.lfm}
32.  
33. { TForm1 }
34.  
35. procedure DownloadFile(const URL, Dest: string);
36. var
37.   F: TFileStream;
38. begin
39.   F := TFileStream.Create(Dest, fmCreate);
40.   try
41.     TFPHTTPClient.SimpleGet(URL, F);
42.   finally
43.     F.Free;
44.   end;
45. end;
46.  
47.  
48. procedure TForm1.Button1Click(Sender: TObject);
49. begin
50. //    DownloadFile('https://www.lazarus-ide.org/index.php/', '/home/aruna/debug/download-test.html');
51.       DownloadFile(Edit1.Text, '/home/aruna/debug/download-test.html');
52. end;
53.  
54. end.
55.  

[zzzzzzz7]

You like the teacher, I want to make a downloader, but when running inward, it always crashes into the main network base address like @Self before, and it's quite aggressive.

The code below has been tested and works on Linux. Your mileage may vary  You must give it the full path including file name to be saved else will choke.

EDIT: The attached ZIP is for you to test and explore.

Code: Pascal  [Select][+][-]

1. unit Unit1;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils, Forms, Controls, Graphics, Dialogs, StdCtrls,
9.   fphttpclient, opensslsockets;
10.  
11.  
12. type
13.  
14.   { TForm1 }
15.  
16.   TForm1 = class(TForm)
17.     Button1: TButton;
18.     Edit1: TEdit;
19.     procedure Button1Click(Sender: TObject);
20.   private
21.  
22.   public
23.  
24.   end;
25.  
26. var
27.   Form1: TForm1;
28.  
29. implementation
30.  
31. {$R *.lfm}
32.  
33. { TForm1 }
34.  
35. procedure DownloadFile(const URL, Dest: string);
36. var
37.   F: TFileStream;
38. begin
39.   F := TFileStream.Create(Dest, fmCreate);
40.   try
41.     TFPHTTPClient.SimpleGet(URL, F);
42.   finally
43.     F.Free;
44.   end;
45. end;
46.  
47.  
48. procedure TForm1.Button1Click(Sender: TObject);
49. begin
50. //    DownloadFile('https://www.lazarus-ide.org/index.php/', '/home/aruna/debug/download-test.html');
51.       DownloadFile(Edit1.Text, '/home/aruna/debug/download-test.html');
52. end;
53.  
54. end.
55.  

//
//Thank you,sir. FileDownLoader.zip（49.85 kB )
//【https://forum.lazarus.freepascal.org/index.php?action=dlattach;topic=74113.0;attach=86744】 but I clicked the button but //nothing happened, no download occurred, nothing happened on Windows 10
//

[rvk]

//
//Thank you,sir. FileDownLoader.zip（49.85 kB )
//【https://forum.lazarus.freepascal.org/index.php?action=dlattach;topic=74113.0;attach=86744】 but I clicked the button but //nothing happened, no download occurred, nothing happened on Windows 10
//

So what file (URL) are you trying to download?

Maybe it's protected somehow (so you can only download it from browsers or it's behind a cloudflare wall or something).

[Aruna]

but I clicked the button but //nothing happened, no download occurred, nothing happened on Windows 10

- Did you type in or copy/paste the URL into the TEdit box then click the button?
- What is the URL to the file you are trying to download? Please share this so we can test and verify URL is legit and functional.
- Does the URL open correctly in a web browser?
- Are you testing on localhost, LAN, or internet?
- Is the internet connection working on that machine?
- Where are you trying to save the downloaded file? (The path in my code will not work unless you created this exact same path on your system)
- Does the destination directory exist?

So what you need to do to get this to work:
1. Create a folder where you want to save the downloded URL
2. Add this folder path to the code and replace :
    DownloadFile(Edit1.Text, '/home/aruna/debug/download-test.html'); with
    DownloadFile(Edit1.Text, '/your/file/download/path/download-test.html');

I am using linux so since your using Windows please adjust the path delimiter from '/' to '\'
3. Enter the URL in the TEdit box next to the button
4. Click the button.

Give me till the end of the day I will send you another zip with full error checking and handling hopefully will make things easier for you.

[Aruna]

Thank you,sir. FileDownLoader.zip（49.85 kB ) but I clicked the button but //nothing happened, no download occurred, nothing happened on Windows 10

As promised, here is a ZIP file containing a tested, cross-platform unit that is fully working. Screenshot attached.

The unit is preconfigured with a default URL for downloading an image. Simply click the button and the image will be downloaded to the following location:

Windows: C:\Users\<YourUsername>\lazarus-forum-question\ (saved as downloaded.png)
Linux/Unix: /home/<username>/lazarus-forum-question/

For the first test, please verify that the file is correctly downloaded to:
C:\Users\<YourUsername>\lazarus-forum-question\downloaded.png

Once confirmed, you can proceed to the next stage.

Pressing F4 toggles the input mode: it enables the TEdit so the user can enter a custom download URL. Pressing F4 again restores the original preloaded URL.

[Handoko]

~edited~

Aruna's code works. Tested on Linux. But running the code, most likely you will get response 403. Error 403 means the server receive your request but refusing it.
https://en.wikipedia.org/wiki/HTTP_403

For security and resource wasting prevention, many websites do not allow scrappers and bad bots. Aruna's code works correctly if you try to download from:
https://www.blogger.com/img/logo_blogger_40px.png

To make it to be able to download from more websites, you should provide more information in your TFPHTTPClient.Header especially the UserAgent. A visitor without User Agent will be treated as a bad bot.