add new functionnality to filezilla: exif thumbnail preview

[cacabuda]

Hello,
it could be very usefull for filezilla to have an icon mode showing image exif thumbnail.
Filezilla would not download the whole images but only exif thumbnail section of photo if exists.
So that we could choose photos to download from ftp server because up to know we need to download the whole images to see what the images are about.
You could even extend this principle to show image exif informations before downloading.
What do you think about that?
Regards,
Yves

[botg]

Filezilla would not download the whole images but only exif thumbnail section of photo if exists.

FTP doesn't support range transfers. Doing so would put tremendous stress on the FTP server, and, depending on the way the file is layed out stored, would actually be slower than simply transferring the whole file.

Oh, and before I forget: Exif doesn't seem to be a maintained standard by any recognized standards body.

[cacabuda]

FTP doesn't support range transfers. => Ok you seems to say it is impossible to download part of a file using FTP. You sure? You can't read first octets and decide to interrupt transfert?

depending on the way the file is layed out stored, would actually be slower than simply transferring the whole file.=> I don't understand, the exif section is located at begining of the file

Oh, and before I forget: Exif doesn't seem to be a maintained standard by any recognized standards body. => I don't understand? Exif is standard now and thumbnails are put by every camera now

[botg]

Ok you seems to say it is impossible to download part of a file using FTP. You sure? You can't read first octets and decide to interrupt transfert?

One can do that, however the server will have already read additional data from the file and sent it over the network, it just hasn't arrived at the client yet. Depending on things like available bandwidth and buffer sizes, this can be in the megabyte range


To quote Wikipedia:

Apart from not being a maintained standard, the Exif format has a number of drawbacks, mostly relating to its use of legacy file structures.

The derivation of Exif from the TIFF file structure using offset pointers in the files means that data can be spread anywhere within a file, which means that software is likely to corrupt any pointers or corresponding data that it doesn't decode/encode. For this reason most image editors damage or remove the Exif metadata to some extent upon saving.[10]

[audiopro]

If you don't know what the photos are, how can you decide from a small thumbnail whether it is required?
You need to create a contact sheet, from the directory.

[cacabuda]

Dear all,
thanks for your answers. As you can see i'm totaly novice but i want to participate to Filezilla improvements.
Regarding answers:
@botg:
* i saw your wikipedia article (http://en.wikipedia.org/wiki/Exif) showing exif drawbacks. ok exif could needs to be replaced but it is today format used by every camera.
* What is interresting in this article is that it tells you need to read only 64kbytes to have all exifs datas... due to exif limitations
* I understood your notice about pointers, but From http://exif.org/specifications.html you can have access to Exif2-2.PDF. p9 show structure of image used in exif v2.2 used by cameras:as i said exif datas should be at begining of most images
* I didn't intend to edit picture
@audiopro: i didn't intend to make any modifications on the server as i think it should/can be avoided and you don't have always autorizations to do that

One can do that, however the server will have already read additional data from the file and sent it over the network, it just hasn't arrived at the client yet. Depending on things like available bandwidth and buffer sizes, this can be in the megabyte range

=>i understand your point. I think you are expert enough to find perhaps a solution for this problem. What i feel is that when i get files using Filezilla, the downloadings can be multiples, made in parallel, whith pause and resume if allowed by server. So perhaps you can manage priorities and so on for getting rid of the problem. I don't know.

Personnaly i made in php a file that generates automatically a web album page showing image preview using exif thumbnail datas. But it is done on server side! So I interrested me about doing ftp using php (client side) and if i'm not mistaking, i discovered that some php functions could be used through ftp (adding more commands than basic ftp commands like get, send)... In c/c++ there are exif libraries allowing to read thumbnail without loading all file. So i asked myself perhaps it is possible to get thumbnail information of image without downloading whole image.

Thanks again,
Yves

[cacabuda]

Hello again,

just for information, it is possible to specify to download by ftp only part of begning file. like using curl command for example. That is you don't overload server.
that is, what i ask should be very simple, not working on every server or every picture, using basic curl, but allowing to receive exif header, thumbnail and display it before asking downloading it.
i will try to do it myself formy own purpose, but i think it would have been better if filezilla team offered this optionnal functionnality.
I don't think my idea is bad at all

Regards,

[cacabuda]

Dear All,
it works!
i putted on my webserver jpeg image >1Mo with exif datas inside and thumbnail image in it (created using exifer).
then i used curl.exe program and command to get first 64kByte of image
(it's something like curl ftp://myserveradress/myimage.jpg -r 0-64000 --user username:password -o header.jpg)
Then i get only 64kb of image on server (not more needed to obtain all exif datas if looking at Exif standard>2.2)
Then if i use exifer or exiftoolgui or so on i find in my 64kb file all the exif datas of my 1Mo server image
Now i know this work so simply i will probably writte my code in c or simply in python (using pycurl module)
I think Filezilla should thinl of that, but i can't force to drink water people that is not thirsty.
Regards,

[botg]

curl does this by violently closing the data connection mid-transfer. Read above why this is a bad idea.

[cacabuda]

hi,

and thanks,

I think i already understood your point of view: if i remember, overloading server, opening too many connections, mismatches between sending and receiving after closing connection and so on.
i don't think there is bad idea, i think only there are bad solutions. All is to find a good one and not declare from begining it is bad idea because it will work like that. Try to re-think from scratch like a beginner using your knowledge and perhaps you will find a solution

From my side, as i said i will develop my own solution for my own purpose, i have one server and the user number on it is very limited. i will see at use how it will works.

regarding curl, i don't know really how it works, perhaps you are right to say it is forcing abrupt closing. but it is surprising as i know you can decide to download a file in multiple parts defining size of parts, in the same time using same type of command i gave.

regards,

[botg]

The solution is obvious, extend the FTP specifications to add a command for range transfers.