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[Gary C.]

Hi

I think this is the correct forum area to post this.

I am using the latest release of GBC and have undertaken a minimal amount of customisation (hiding the sidebar and redirecting to an alternative application end page).

I have an issue with the displaying of images within a display array in IE (various versions). It works in Chrome.

The symptom is that the image is just not displayed and I am not sure if it is my approach, a browser issue or GBC. The 4GL code I am using looks like that below:

Code:

DEFINE imageA dynamic array of record
    description string,
    img byte
END RECORD,
imageID INTEGER,
imageDesc STRING

DECLARE imgC cursor FOR....

FOREACH imgC INTO imageID, imageDesc 
    LET imageA[imagA.getLength() + 1].description = imageDesc
    LOCATE imageA[imagA.getLength()].img in file
    SELECT imageblob INTO imageA[imagA.getLength()].img FROM imagetable
        WHERE id = imageID
END FOREACH

DISPLAY ARRAY imageA to imageR.*

END DISPLAY

As ever, any help would be appreciated.

Gary
 

[Sebastien F.]

Hello Gary,

Regarding the SQL/BYTE usage in your code example, to me it looks good.

It can however be optimized to avoid a second SELECT inside the FOREACH.

For an example see this page:

http://4js.com/online_documentation/fjs-fgl-manual-html/#c_fgl_variables_LOCATE.html

See also:

http://4js.com/online_documentation/fjs-fgl-manual-html/#c_fgl_images_dynamic_images.html

A sample is available in FGLDIR/demo/Widgets/ImageList.4gl

Seb

[Gary C.]

Hi

In case anyone else comes across this, this is what I have done to overcome the problem.

When I inspected the image element in the browser I could see that it's URL was pointing to the user's temporary session area and had been given a random number as a name. However, there was no file type extension.

I think Chrome must be looking at the content to infer the file is an image whereas IE does not.

So, I changed the code to use the LOCATE IN FILE instruction for the blob and specified the original file name when the image was uploaded. Now the URL has a file type and displays across all browsers.

Gary

[Sebastien F.]

Hi Gary,

Thanks for sharing this!

You mean that you have to use:
 

Code:

LOCATE var IN FILE filename

with file image extension instead of:
 

Code:

LOCATE var IN FILE

to make it work?

We need to double check this and may add it to the programming pattern... or handle the case automatically.

Note: Since the LOCATE file name is no longer unique, you may want to consider concurrent programs using the same file names.
You may want to produce a temporary file name with os.Path.makeTempName() and concat the image format extension...

Seb

[Sebastien F.]

Gary,

Please open a support case and provide all configuration and version details.

I have just tested the ImageList demo with FGL 3.10 and fglgar war and Microsoft Edge and images are visible.

I cannot test IE.

Seb

[Sisavanh S.]

Hi Gary,

Indeed, since GAS 3.00.35 and GAS 3.10, for security reasons, we have activated by default the header "X-Content-Type-Options" with value "nosniff".
In as.xcf, you can check:

Code

<HEADER Name="X-Content-Type-Options">nosniff</HEADER>

As you noted, now the file to display requires an extension.
As you did, you can use

Code

LOCATE var IN FILE filename

where the filename has an extension.

For example:

Code

LET filename = os.Path.makeTempName() || ".jpg"

You can use "os.Path.makeTempName()" to create your temporary file.

Freeing your BYTE will automatically remove the related temporary file.
For example:

Code

FREE var

We will add a migration note about this in the manuals.

Thanks for reporting and sharing.
Best regards,
Sisa.

[Sisavanh S.]

Hi again,

More details about this issue.
The issue happens on Internet Explorer 11 not on Edge, Chrome or Firefox.

"X-Content-Type-Options" is applied on "script" and "style" files:
https://developer.mozilla.org/fr/docs/Web/HTTP/Headers/X-Content-Type-Options.

Anyway, better set extensions to your files to avoid any misbehavior.

Best regards,
Sisa.