Serving html page containing images

[marcovaldo 1]

Hi All,

Beside using MARS as a REST server using JSON interface
I also want to serve a few plain HTML pages used for status display with browsers.

There shall be a table returned containing text and if possible images/icons beside that
like
Device1   online   [an image]
Device2   offline  [ an other image]

Is there any example how to do this?
The images are shown as broken in browser.

Does this need multiple endpoints to serve ?
(One for the text and then one extra for every image, as the browser will
do several  HTTP connections to retrieve them)

I am using Indy in a windows service (alternatively startable via /GUI as application)

Kind Greetings,
M.

[Attila Kovacs 631]

of course, tons of

 

https://www.w3schools.com/html/html_tables.asp

https://www.w3schools.com/html/html_images.asp

 

37 minutes ago, marcovaldo said:

Does this need multiple endpoints to serve ?

 

No, you have to serve the requested file. https://www.rfc-editor.org/rfc/rfc2616   9.3 GET

Indy should have already implemented that for you.

 

Edited January 10, 2023 by Attila Kovacs

[marcovaldo 1]

Many Thanks Attila, for your quick help!

I am trying to play with the Bootstrap Server example
(as I can edit html without compile)

In Mars this page is served as follows
 

function THelloWorldResource.SayHelloWorld: string;
var
  LStreamReader: TStreamReader;
begin
  LStreamReader := TStreamReader.Create('..\www\helloworld.html', TEncoding.UTF8);
  try
    Result := LStreamReader.ReadToEnd;
  finally
    LStreamReader.Free;
  end;
end;

What works: if the IMG is served from external server
What doesn't work: if the IMG is referenced to local filesystem (location of binary)
i thought that WEB root is application folder (maybee I am wrong?)
Just try to find something in the web about this ....

Greetings!

 

 

[marcovaldo 1]

Fixed:

1) Created a separate handler in MARS for images (similar to MARSContentType Demo):
 

    [GET, Path('/img/{*}'), Produces('image/jpg')]
    function ServerImg([PathParam('*')] AllStrings: string): TStream;

and
 

function TDominoServerResource.ServerImg([PathParam('*')] AllStrings: string): TStream;
begin
  Result := TFileStream.Create('Sample.jpg', fmOpenRead or fmShareDenyWrite);
end;

Note: This sample serves only one fixed image to all requests. AllStrings needs to be processed still...

2) In HTML I had to take care not only on HTML SRC path but also on MARS/REST path

<img src="/rest/default/myservername/img/Sample.jpg">

Waterfall mode of Chrome Browser is your friend!
(as it showed what is requested by browser)

Greetings to All, 
M.

[Attila Kovacs 631]

Ahh I see now! This is great. You can decorate the handler method in mars and that's it?

[marcovaldo 1]

The slightly extended version of the handler now sends
differnt images from  [Application Bin folder]\img   folder

 

function TDominoServerResource.ServerImg([PathParam('*')] AllStrings: string): TStream;
begin
//DebLog.DebOut('ImageRequest:'+AllStrings+'*');
//AllStrings contains plain image filename
Result := TFileStream.Create('img\'+AllStrings, fmOpenRead or fmShareDenyWrite);
end;

Why I wanted that MARS is also serving HTML pages for browser
- Status Display
- Setup functions (as my app normally is running as service)

My old application used a telnet connection for that purpose but
I bet that customer IT is nowadays unhappy having an open telnet connection
on a productive server.

The http connection can be protected by various auth methods..

 

Greetings

[Attila Kovacs 631]

Make sure you are not exposing more that you want. Make a root directory where your server not going below that dir. One could request with /../ .... files you don't want to expose.

[marcovaldo 1]

Attila, thank you for advice!
Any advice that this is very welcome, as security is always a very important aspect of IT...