CTC 138: Image hosting dynamic relocation scheme

We have a big cheap server which is very slow and a small expensive server which is very fast. We have a website and all images are currently hosted on the big slow server. We need to use the small fast server for images to improve performance. However, only a small number of images will fit on the small fast server. Luckily for us, the access pattern on the website is lopsided towards popular images, so we can store only those in the fast server. We need a scheme to dynamically relocate images from the big slow server to the small fast server. Images on the small fast server automatically disappear after 24 hours, so you need to keep a MySQL database entry to track the expiration time. The HTML IMG SRC tag attribute generated from our PHP scripts need to be updated dynamically when this happens, to point at the fast server. Which means, we need a MySQL table to figure out the correct IMG SRC for every image. One part of the solution should include periodic batch updates, to avoid slowing down the website by including too much logic in the web pages. That means, you must have a scheme where the IMG SRC attribute actually points to a server-side PHP script where all the logic happens. There are many ways to do this. If you cannot think of how to correctly point IMG SRC to a PHP script and make it work correctly in all browsers, then please DO NOT BID, because it means you are unqualified for this project. This task is hard to understand but is not hard to do once you get it. But I don't have time to explain further, so please do not bid unless you get it. ## Deliverables Currently (see photo), we use a PHP Class for the PHP pages to retrieve the photo URL to be placed in the IMG SRC tag. This is the class you will need to modify. Currently this class is only 10 lines of code. We expect when you finish the project, the class will have around 300 to 500 lines of code. The two functions getMainPhoto() and getOtherPhoto() must remain compatible with the same parameters. *** Frequently Asked Questions by Workers and their Answers: *1.** If images from fast server are cleaned after 24 hours then where will be the images of fast server and then how to get image from fast server? **Answer:** Once an image is cleaned, it is lost. It can only be retrieved again from the slow server. **2.** Do you upload images to fast server manually? **Answer:** No. **3.** The script will run to the fast server...if image not found in fast server then it will get image from slow server and save it to fast server...correct? **Answer:** Correct. **4.** If images is not found on both server then what to do? **Answer:** Die with an error. **5.** URLs of fast and slow servers **Answer:** Slow server URL was already provided in the project screen shot ([[login to view URL]][1]). Fast server URL is "[http://localhost][2]". **6.** What is the access for moving the images from the slow server to the fast server. **Answer:** It can be done by a script. **7.** Is there a module to be developed for the same, or there exists a module for this, which takes in the image name moves it and returns the URL? **Answer:** If the bidder could develop this then I will pay extra, otherwise I could pay less and will provide this script myself. The actual script needs to use a Cloud API to move the image. **8.** Can you tell the website URL and domain name used for each server? I believe the big server is mapped to a sub domain ([login to view URL]) and the domain ([login to view URL]) to the fast server? **Answer:** No, they are on different domains. Slow server is mlsni.com. Fast server is localhost. **9.** Do I have to monitor the requests for images and determine which images are popular or this data is to be read from the database (some sort of popularity ranking). **Answer:** Sort of. Once an image is request the first time, it is considered Popular. **10.** Is big server accessible through HTTP or only from small server or direct disk access to images are possible? **Answer:** It is only accessible through HTTP and FTP. **11.** What is the average size of each image and how many do you think can be stored on the small server? **Answer:** The small server has infinite storage, but charges a fee per Gigabyte, so I would like to keep max 1000 to 2000 images. **12.** Will I get FTP access to servers while developing? I'll try to test without modifying any in production pages. **Answer:** This is negotiable. I prefer bidders who have their own server. But if your bid is really low, I can loan my server. **13.** What is the php version and which web server are you using? **Answer:** PHP 5.3, Apache2 **14.** How exactly you figure out the image popularity, assuming it somehow happens, and there are some function isImagePopular($img)? **Answer:** Every image which is requested is popular. Unpopular have zero requests. **15.** About actual relocation of images from slow to fast server. Tell me please on what server is php code running? **Answer:** PHP runs on the fast server, but the images are stored on the cloud. **16.** If it is running on any 3d server, tell me please, what interface will be used to store images on fast server? **Answer:** There will be a script using Rackspace Cloud API. If you can develop this script, I will pay extra. If you want me to develop it, I expect a low bid. **17.** Images on the small fast server automatically disappear after 24 hours, so you need to keep a MySQL database entry to track the expiration time. Is that 24 hours from relocation from slow server, or from last request to those images? **Answer:** That's 24 hours from the last request. * * *This broadcast message was sent to all bidders on Sunday Aug 14, 2011 5:08:13 PM (by sub-account person id [#7902445][3]): Hello workers, The questions asked by you have been answered in detailed requirement. Please check there and get back to us. We will select a worker who has understood requirements completely.