Using fopen or SQL to check image
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From: Ashley Sheridan on 25 Jun 2010 15:02 On Fri, 2010-06-25 at 21:01 +0200, Peter Lind wrote: > On 25 June 2010 20:59, Ashley Sheridan <ash(a)ashleysheridan.co.uk> wrote: > > > > On Fri, 2010-06-25 at 20:57 +0200, Peter Lind wrote: > > > > On 25 June 2010 19:35, Ashley Sheridan <ash(a)ashleysheridan.co.uk> wrote: > > > On Fri, 2010-06-25 at 19:31 +0200, Karl Cifius wrote: > > > > > >> Hi, > > >> > > >> I'm making a Facebook application that can generate images to user's > > >> albums. To publish a story a thumbnail of this image is stored on my > > >> server. Since this server currently is very limited I want to be able > > >> to clean these thumbnails pretty often. > > >> > > >> To not get broken links in older facebook stories the address to the > > >> thumbnail is a php script that checks if the thumbnail is available > > >> and returns it, or otherwise returns a default thumbnail. > > >> > > >> I have solved this using the following code: > > >> > > >> $tImage = $_GET['i']; > > >> $tURL = "upload/$tImage.jpg"; > > >> if(!($fp=fopen($tURL,"rb"))){ > > >> header("Location: thumb.jpg"); > > >> }else{ > > >> header("Location: upload/$tImage.jpg"); > > >> fclose($fp); > > >> } > > >> > > >> My question is if it would be better to have a mysql database with > > >> information about the thumbnail and check if the image is there, > > >> instead of checking if the image file can be loaded? What is the most > > >> optimized approach if I start to gain traffic? > > >> > > >> > > >> Thanks, > > >> > > >> /Karl > > >> > > > > > > > > > I think checking for the existence of a file is probably going to be the > > > quicker approach. Unless you have a server with loads of RAM and your DB > > > is very small, it's unlikely your DB will exist entirely in memory, so > > > you will at some point have to access the files that the DB uses, even > > > though this is done by the server automatically. > > > > > > On another note, I would try to sanitise that $_GET variable a bit, as > > > it could lead to issues down the line later. Maybe limit the string to > > > patterns you expect for an image URL. > > > > > > Thanks, > > > Ash > > > http://www.ashleysheridan.co.uk > > > > > > > Might be quicker to do with a .htaccess file - you can avoid loading php at all. > > > > Regards > > Peter > > > > > > > > PHP can do things that .htaccess can't, like verify a specific ID has access to an image, etc. > > > > I must've missed the part in the code where the ID was checked ... > Nope, still can't find it. > > Regards > Peter > > > -- > <hype> > WWW: http://plphp.dk / http://plind.dk > LinkedIn: http://www.linkedin.com/in/plind > BeWelcome/Couchsurfing: Fake51 > Twitter: http://twitter.com/kafe15 > </hype> It wasn't in the example, but generally I've found the only reason someone ever thinks of doing something like this rather than directly link to the image is for some sort of validation reason. I assumed it was a slimmed-down code sample that only showed us what we needed. Thanks, Ash http://www.ashleysheridan.co.uk
From: Peter Lind on 25 Jun 2010 15:07 On 25 June 2010 21:02, Ashley Sheridan <ash(a)ashleysheridan.co.uk> wrote: > > On Fri, 2010-06-25 at 21:01 +0200, Peter Lind wrote: > > On 25 June 2010 20:59, Ashley Sheridan <ash(a)ashleysheridan.co.uk> wrote: > > > > On Fri, 2010-06-25 at 20:57 +0200, Peter Lind wrote: > > > > On 25 June 2010 19:35, Ashley Sheridan <ash(a)ashleysheridan.co.uk> wrote: > > > On Fri, 2010-06-25 at 19:31 +0200, Karl Cifius wrote: > > > > > >> Hi, > > >> > > >> I'm making a Facebook application that can generate images to user's > > >> albums. To publish a story a thumbnail of this image is stored on my > > >> server. Since this server currently is very limited I want to be able > > >> to clean these thumbnails pretty often. > > >> > > >> To not get broken links in older facebook stories the address to the > > >> thumbnail is a php script that checks if the thumbnail is available > > >> and returns it, or otherwise returns a default thumbnail. > > >> > > >> I have solved this using the following code: > > >> > > >> $tImage = $_GET['i']; > > >> $tURL Â = "upload/$tImage.jpg"; > > >> if(!($fp=fopen($tURL,"rb"))){ > > >> Â Â header("Location: thumb.jpg"); > > >> }else{ > > >> Â Â header("Location: upload/$tImage.jpg"); > > >> Â Â fclose($fp); > > >> } > > >> > > >> My question is if it would be better to have a mysql database with > > >> information about the thumbnail and check if the image is there, > > >> instead of checking if the image file can be loaded? What is the most > > >> optimized approach if I start to gain traffic? > > >> > > >> > > >> Thanks, > > >> > > >> /Karl > > >> > > > > > > > > > I think checking for the existence of a file is probably going to be the > > > quicker approach. Unless you have a server with loads of RAM and your DB > > > is very small, it's unlikely your DB will exist entirely in memory, so > > > you will at some point have to access the files that the DB uses, even > > > though this is done by the server automatically. > > > > > > On another note, I would try to sanitise that $_GET variable a bit, as > > > it could lead to issues down the line later. Maybe limit the string to > > > patterns you expect for an image URL. > > > > > > Thanks, > > > Ash > > > http://www.ashleysheridan.co.uk > > > > > > > Might be quicker to do with a .htaccess file - you can avoid loading php at all. > > > > Regards > > Peter > > > > > > > > PHP can do things that .htaccess can't, like verify a specific ID has access to an image, etc. > > > > I must've missed the part in the code where the ID was checked ... > Nope, still can't find it. > > Regards > Peter > > > -- > <hype> > WWW: http://plphp.dk / http://plind.dk > LinkedIn: http://www.linkedin.com/in/plind > BeWelcome/Couchsurfing: Fake51 > Twitter: http://twitter.com/kafe15 > </hype> > > It wasn't in the example, but generally I've found the only reason someone ever thinks of doing something like this rather than directly link to the image is for some sort of validation reason. I assumed it was a slimmed-down code sample that only showed us what we needed. > Ahh, I see. I assumed the OP would have told us if that was the case - I prefer answering the stated questions instead of guessing at what they are. Regards Peter -- <hype> WWW: http://plphp.dk / http://plind.dk LinkedIn: http://www.linkedin.com/in/plind BeWelcome/Couchsurfing: Fake51 Twitter: http://twitter.com/kafe15 </hype>
From: Karl Cifius on 26 Jun 2010 05:30
Thanks Ashley and Peter for your suggestions, I've definitely learned some new stuff here. Best, Karl On 25 jun 2010, at 21.07, Peter Lind <peter.e.lind(a)gmail.com> wrote: > On 25 June 2010 21:02, Ashley Sheridan <ash(a)ashleysheridan.co.uk> > wrote: >> >> On Fri, 2010-06-25 at 21:01 +0200, Peter Lind wrote: >> >> On 25 June 2010 20:59, Ashley Sheridan <ash(a)ashleysheridan.co.uk> >> wrote: >>> >>> On Fri, 2010-06-25 at 20:57 +0200, Peter Lind wrote: >>> >>> On 25 June 2010 19:35, Ashley Sheridan <ash(a)ashleysheridan.co.uk> >>> wrote: >>>> On Fri, 2010-06-25 at 19:31 +0200, Karl Cifius wrote: >>>> >>>>> Hi, >>>>> >>>>> I'm making a Facebook application that can generate images to >>>>> user's >>>>> albums. To publish a story a thumbnail of this image is stored >>>>> on my >>>>> server. Since this server currently is very limited I want to be >>>>> able >>>>> to clean these thumbnails pretty often. >>>>> >>>>> To not get broken links in older facebook stories the address to >>>>> the >>>>> thumbnail is a php script that checks if the thumbnail is >>>>> available >>>>> and returns it, or otherwise returns a default thumbnail. >>>>> >>>>> I have solved this using the following code: >>>>> >>>>> $tImage = $_GET['i']; >>>>> $tURL = "upload/$tImage.jpg"; >>>>> if(!($fp=fopen($tURL,"rb"))){ >>>>> header("Location: thumb.jpg"); >>>>> }else{ >>>>> header("Location: upload/$tImage.jpg"); >>>>> fclose($fp); >>>>> } >>>>> >>>>> My question is if it would be better to have a mysql database with >>>>> information about the thumbnail and check if the image is there, >>>>> instead of checking if the image file can be loaded? What is the >>>>> most >>>>> optimized approach if I start to gain traffic? >>>>> >>>>> >>>>> Thanks, >>>>> >>>>> /Karl >>>>> >>>> >>>> >>>> I think checking for the existence of a file is probably going to >>>> be the >>>> quicker approach. Unless you have a server with loads of RAM and >>>> your DB >>>> is very small, it's unlikely your DB will exist entirely in >>>> memory, so >>>> you will at some point have to access the files that the DB uses, >>>> even >>>> though this is done by the server automatically. >>>> >>>> On another note, I would try to sanitise that $_GET variable a >>>> bit, as >>>> it could lead to issues down the line later. Maybe limit the >>>> string to >>>> patterns you expect for an image URL. >>>> >>>> Thanks, >>>> Ash >>>> http://www.ashleysheridan.co.uk >>>> >>> >>> Might be quicker to do with a .htaccess file - you can avoid >>> loading php at all. >>> >>> Regards >>> Peter >>> >>> >>> >>> PHP can do things that .htaccess can't, like verify a specific ID >>> has access to an image, etc. >>> >> >> I must've missed the part in the code where the ID was checked ... >> Nope, still can't find it. >> >> Regards >> Peter >> >> >> -- >> <hype> >> WWW: http://plphp.dk / http://plind.dk >> LinkedIn: http://www.linkedin.com/in/plind >> BeWelcome/Couchsurfing: Fake51 >> Twitter: http://twitter.com/kafe15 >> </hype> >> >> It wasn't in the example, but generally I've found the only reason >> someone ever thinks of doing something like this rather than >> directly link to the image is for some sort of validation reason. I >> assumed it was a slimmed-down code sample that only showed us what >> we needed. >> > > Ahh, I see. I assumed the OP would have told us if that was the case - > I prefer answering the stated questions instead of guessing at what > they are. > > Regards > Peter > > -- > <hype> > WWW: http://plphp.dk / http://plind.dk > LinkedIn: http://www.linkedin.com/in/plind > BeWelcome/Couchsurfing: Fake51 > Twitter: http://twitter.com/kafe15 > </hype> |