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Groups > comp.lang.javascript > #39391

Re: blob from createobjecturl

From Thomas 'PointedEars' Lahn <PointedEars@web.de>
Newsgroups comp.lang.javascript
Subject Re: blob from createobjecturl
Date 2021-01-24 22:26 +0100
Organization PointedEars Software (PES)
Message-ID <3096479.44csPzL39Z@PointedEars.de> (permalink)
References <6sednXpeKZTIepH9nZ2dnUU7-UHNnZ2d@westnet.com.au> <4594399.GXAFRqVoOG@PointedEars.de> <-tudnfIaWbymRpD9nZ2dnUU7-S_NnZ2d@westnet.com.au>

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Andrew Poulos wrote:

> On 24/01/2021 3:01 pm, Thomas 'PointedEars' Lahn wrote:
>> Andrew Poulos wrote:
>>> A web page I'm working on create a number of images using
>>>
>>> fetch(url)
>>>     .then(response => {
>>>       return response.blob();
          ^^^^^^^^^^^^^^^^^^^^^^^
>>>     })
>>>     .then(b => {
>>>       myImage.src = URL.createObjectURL(b);
>>>     })
>>>     .catch(err => console.log(err));
>>>
>>> The user can create/destroy as many images as they want.
>>>
>>> If at some point the user wants to save an image, the page needs to send
>>> it to the server. Is it ok to send myImage.src to a PHP server and the
>>> server can correctly handle it or do I need to send the blob that was
>>> used to create the object URL?
>> 
>> Can the user modify the image?  If not, and the server where the image is
>> stored is the same from which it was obtained, then simply PUT or POST
>> the original URI and let the server map that to the local filesystem. 
>> This is much less expensive than PUTting/POSTing the BLOB.
> 
> Too easy :-) Thanks,

You’re welcome :)

> I posted the original URI and the server handled it.

One thing to keep in mind, though: This will use the image resource *as 
retrievable at the time of POST*, not at the time of GET.

So if it has changed or has become unavailable in the meantime, then the 
change/unavailability will be propagated to the user’s image album.  For a 
*snapshot*, you have to PUT or POST the BLOB as formerly retrieved by the 
client.
 
>> Otherwise PUT or POST the BLOB and let the server handle that.
> 
> The created BLOB isn't saved (whereas the URI is) so I would have to
> fetch it again.

You would just have to save it before you now return it, provided you have 
control over that part of the code.  See above.

-- 
PointedEars
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Thread

blob from createobjecturl Andrew Poulos <ap_prog@hotmail.com> - 2021-01-24 14:19 +1100
  Re: blob from createobjecturl Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2021-01-24 05:01 +0100
    Re: blob from createobjecturl Andrew Poulos <ap_prog@hotmail.com> - 2021-01-25 07:40 +1100
      Re: blob from createobjecturl Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2021-01-24 22:26 +0100
  Re: blob from createobjecturl JJ <jj4public@gmail.com> - 2021-01-24 19:29 +0700
    Re: blob from createobjecturl Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2021-01-24 22:18 +0100
  Re: blob from createobjecturl "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2021-01-24 09:18 -0800

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