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Zinc question (may be this is an HTML one)

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Stéphane Ducasse

Zinc question (may be this is an HTML one)

Hi sven and others

While trying to improve microdown I have the following question.

How can I have a more generic getImage: method.

Right now I use getPng: and I would like to support getPng: and getJpeg.

I saw that there is getImageOfType: mimeType fromUrl: urlObject

getImageOfType: mimeType fromUrl: urlObject

| client |

(client := self client)

url: urlObject;

accept: mimeType;

enforceHttpSuccess: true;

enforceAcceptContentType: true;

get.

"ImageReadWriter does automatic type detection"

^ ImageReadWriter formFromStream: client entity readStream

So it looks like what I want except that I do not know how to specify a Mime

So I did

ZnEasy

getImageOfType: (ZnMimeType main: 'image' sub: '*')

fromUrl: 'http://pharo.org/files/pharo.png'

Now I would like to know if this is the correct way to do it.

I could imagine that we could give a set of possible mime types.

--------------------------------------------

Stéphane Ducasse

http://stephane.ducasse.free.fr / http://www.pharo.org

03 59 35 87 52

Assistant: Aurore Dalle

FAX 03 59 57 78 50

TEL 03 59 35 86 16

S. Ducasse - Inria

40, avenue Halley,

Parc Scientifique de la Haute Borne, Bât.A, Park Plaza

Villeneuve d'Ascq 59650

France

Sven Van Caekenberghe-2

Re: Zinc question (may be this is an HTML one)

Hi Stef,

> On 20 Oct 2020, at 09:35, Stéphane Ducasse <[hidden email]> wrote:
>
> Hi sven and others
>
>
> While trying to improve microdown I have the following question.
> How can I have a more generic getImage: method.
>
> Right now I use getPng: and I would like to support getPng: and getJpeg.
>
> I saw that there is getImageOfType: mimeType fromUrl: urlObject
>
>
> getImageOfType: mimeType fromUrl: urlObject
> | client |
> (client := self client)
> url: urlObject;
> accept: mimeType;
> enforceHttpSuccess: true;
> enforceAcceptContentType: true;
> get.
> "ImageReadWriter does automatic type detection"
> ^ ImageReadWriter formFromStream: client entity readStream
>
> So it looks like what I want except that I do not know how to specify a Mime
>
> So I did
>
> ZnEasy
> getImageOfType: (ZnMimeType main: 'image' sub: '*')
> fromUrl: 'http://pharo.org/files/pharo.png'
>
> Now I would like to know if this is the correct way to do it.
> I could imagine that we could give a set of possible mime types.

This is an HTTP question (the protocol, not HTML the document format).

And you solved your problem well, I never tried it like that myself ;-)

I would not write it differently.

Like the comment says, it will only work with those types recognised by ImageReadWriter, which are the most common ones, JPG, GIF and PNG.

Image/* is a wildcard matching any image type, and there are many, many more.

The current mechanism in Zinc with #accept: and #enforceAcceptContentType: true assumes a singular 'Accept' header. But indeed, technically, it is possible to specify more than one.

For example, this also works:

ZnClient new
url: 'http://pharo.org/files/pharo.png';
headerAt: 'Accept' add: ZnMimeType imageGif asString;
headerAt: 'Accept' add: ZnMimeType imagePng asString;
headerAt: 'Accept' add: ZnMimeType imageJpeg asString;
contentReader: [ :entity | ImageReadWriter formFromStream: entity readStream ];
get.

But I have to think a bit about this issue.

Another approach is to use the extension of the URL.

ZnMimeType forFilenameExtension: 'http://pharo.org/files/pharo.png' asUrl file asFileReference extension.

It all depends at what level you want to tell your user they tried getting an unsupported file type.

Sven

> S.
>
>
> --------------------------------------------
> Stéphane Ducasse
> http://stephane.ducasse.free.fr / http://www.pharo.org
> 03 59 35 87 52
> Assistant: Aurore Dalle
> FAX 03 59 57 78 50
> TEL 03 59 35 86 16
> S. Ducasse - Inria
> 40, avenue Halley,
> Parc Scientifique de la Haute Borne, Bât.A, Park Plaza
> Villeneuve d'Ascq 59650
> France
>

Stéphane Ducasse

Re: Zinc question (may be this is an HTML one)

This is an HTTP question (the protocol, not HTML the document format).

Yes this is what I meant but the mail was sent.

And you solved your problem well, I never tried it like that myself ;-)

I would not write it differently.

Like the comment says, it will only work with those types recognised by ImageReadWriter, which are the most common ones, JPG, GIF and PNG.

Image/* is a wildcard matching any image type, and there are many, many more.

The current mechanism in Zinc with #accept: and #enforceAcceptContentType: true assumes a singular 'Accept' header. But indeed, technically, it is possible to specify more than one.

For example, this also works:

ZnClient new
url: 'http://pharo.org/files/pharo.png';
headerAt: 'Accept' add: ZnMimeType imageGif asString;
headerAt: 'Accept' add: ZnMimeType imagePng asString;
headerAt: 'Accept' add: ZnMimeType imageJpeg asString;
contentReader: [ :entity | ImageReadWriter formFromStream: entity readStream ];
get.

Ah this would be better for me because like that I can probably control which exception is raised.

Because we do not support image/svg

But I have to think a bit about this issue.

Another approach is to use the extension of the URL.

ZnMimeType forFilenameExtension: 'http://pharo.org/files/pharo.png' asUrl file asFileReference extension.

It all depends at what level you want to tell your user they tried getting an unsupported file type.

Broad :) but soon you will be my user and you will have the right to complain :)

Sven

S.

--------------------------------------------
Stéphane Ducasse
http://stephane.ducasse.free.fr / http://www.pharo.org
03 59 35 87 52
Assistant: Aurore Dalle
FAX 03 59 57 78 50
TEL 03 59 35 86 16
S. Ducasse - Inria
40, avenue Halley,
Parc Scientifique de la Haute Borne, Bât.A, Park Plaza
Villeneuve d'Ascq 59650
France

--------------------------------------------

Stéphane Ducasse

http://stephane.ducasse.free.fr / http://www.pharo.org

03 59 35 87 52

Assistant: Aurore Dalle

FAX 03 59 57 78 50

TEL 03 59 35 86 16

S. Ducasse - Inria

40, avenue Halley,

Parc Scientifique de la Haute Borne, Bât.A, Park Plaza

Villeneuve d'Ascq 59650

France