Chapter 4. Developer's guide

4.1. ACS 4.0 Photo Album Application Requirements

by Tom Baginski,

4.1.1. Introduction

This document presents the requirements for the ACS 4.0 Photo Album Package, which is a generalized application for storing and displaying groups of photos on a web site. It is intended to build on the experience gained from creating and maintaining a photo album system for the IluvCamp client site.

4.1.2. Vision Statement

Many people want to display photos on the web. Building a simple personal web page with vacation photos is easy and can be done by hand with static html. Building 100 similar web pages for all your friends and relatives would be tedious. More importantly it would be difficult to maintain and scale such a system to support all the users of a large site.

The photo album package provides a convenient and uniform system for uploading, storing, and displaying groups of photos on a web site. It removes the tedious part of building pages to display photos, and allows users more flexibility to maintain and modify their own photo albums. It also removes much of the burden from the owners/maintainers of the site. All of these factors add up to a system that allows community members to easily contribute and view large amounts of compelling content on a site.

The initial version of the package will allow designated users to upload photos into albums and to group albums into a folder hierarchy that other users with appropriate permissions can view and possibly edit.

Future improvement to the photo album package will incorporate additional features developed on various customer sites that allow users to upload photos in bulk through a client applet and to purchase prints of photos presented on the site.

4.1.3. System/Application Overview

The basic content element of the photo album system is a photo. When a user uploads a photo, the system stores attribute data such as caption, story, and title as a single content element. Each photo associated with several (three to start) image elements that store the actual binary files. The image elements, which are created by the server, are standard sized versions of the original photo used for display. Photos and images can have descriptive attributes associated with them. The attributes and binary files can be revised and the system will retain past versions.

Photos are grouped together into albums which can contain 0 or more photos. The albums can have descriptive attribute information that can be revised with history tracking. The albums can be displayed as a unit that allows user to browse through the photos in the album.

Albums can be grouped together into folders that can contain 0 or more albums or other folders.

An instance of the package include pages to display the folders, albums, and photos along with admin pages. Instances can be mounted to different subsite and managed independently. The grouping is included within the instance so that the albums maintain a consistent url even if they are re-sorted to different folders within the instance (as long as the subsite url isn't changed).

The display, grouping, and administration functionality of the photo album package will be included in the initial release of the package. This is intended to be one part of a larger system that will allow bulk uploading and purchasing of photos. These two feature have already been implemented on aD customer sites. ACS 4 versions of these features will be either incorporated into a future version of the photo album package or added as individual packages that depend on the photo album.

The basic tasks of the photo album revolve around storing and displaying content and associated attributes. As such, this package will take advantage of the exiting features of the content repository service package. The content repository can store multiple revisions of content items such as photos and images and their associated attributes. The content repository also provides grouping functions. The acs permission service will be used for access control so view, edit, and administration privileges will be highly customizable. Finally individual photo album instances can be added to subsites to support multiple independent photo albums on the same site.

4.1.4. Use-cases and User-scenarios General Scenarios

  • A young couple just got married. His family shot 20 rolls of film at the wedding and the photographer they hired shot an additional 15 rolls. Now that the wedding is over, this couple must organize their photos. In addition to creating traditional, physical photo albums, they want to publish their photos on the web to share with friends and family all over the world.

    The couple scans the images they want to publish on the web. Most of the images were scanned from the negatives at processing time making it easy for the couple to obtain digital versions of their photographs. The couple creates a new photo album for their wedding, and then adds the following folders: "Engagement photo shoot," "Rehearsal dinner," "Ceremony," "Reception," and "Honeymoon." The honeymoon itself was spent in two different places. The couple creates subfolders for each of these places in their Honeymoon folder.

    Now the folder hierarchy looks like:

        - Wedding
            - Engagement Photo Shoot
            - Rehearsal Dinner
            - Ceremony
            - Reception
            - Honeymoon
                - Fiji - Big Island
                - Fiji - Tokoriki

    The couple now opens a folder, and uploads images. With each image, the couple can specify optional attributes such as the caption for the photo, the story behind the photo, and an identifier to help them locate the physical negatives at a later date.

    Once the images are uploaded, the couple decides to give their parents administrative access to a couple folders. Now their parents can upload additional photos to those folders or modify the attributes of any given photo.


  • The administrator of the "Dogs of the World" subsite on the "All Furry Creatures" web sites wants to provide a way to show pictures of various dog breads. Since the admin is a busy person she doesn't want to upload and manage all of the images herself. She does, however, want to specify the general layout of the various albums and control who can upload images.

    She creates an instance of the photo album within her subsite. Then goes about creating a folder structure such as:

        - Dogs of the World
            -Hunting Dogs
            -Show Dogs
            -Lap Dogs
            -Yappy Dogs
            -Mutts(The coolest)

    She then designates certain users or groups of users that she trusts to manage a given folder and grants them permission to create albums within each folder. These users go about creating albums and uploading appropriate images as they see fit. They cannot create new subfolders, so the folder structure will not become fragmented and disorganized (the admin is both a control and neat freak).

    The admin later realizes that Lap Dogs and Yappy Dogs are basically the same thing so she consolidates the two folders into one called Trouble Dogs.

    Since the point of the dog album is to show off various dogs, she wants the world to be able to see them. She grants view access to all albums within her subsite to the general public.

4.1.6. Requirements Photo Requirements

A photo is a generic content item for user uploaded photos. Each photo will have image content items associated with it that store the actual binary files and any image specific attributes. Photo and image content items can accommodate multiple revisions.

  • VI.A.10 System will store three images associated with a photo: the original image, thumbnail image, and a view-sized image.

  • VI.A.20 System will maintain a revision history for the photos and record which revision is current for given situation.

  • VI.A.30 Images shall be stored so that they can be served efficiently. The system should allow for storing the binary files in either the file system or the database. This should be controlled by a parameter. The initial implementation may only support one storage type, but it should be open to either storage type.

  • VI.A.40 Photos and any revisions have attribute data associated with them. The method and structure for storing these attributes will be decided as part of the design and implementation.

    • VI.A.40.10 System specified attributes. Certain attributes will be specified and maintained by the system. These attributes will include: uploading_user, user_filename, original_file_size, original_width, original_height, original_path, thumb_width, thumb_height, thumb_file_size, thumb_path, view_width, view_height, view_file_size, view_path, caption, upload_date. Other attributes will be determined during the design process.

    • VI.A.40.20 Administrator specified attributes. The site administrator can specify custom attributes of photos and if these attributes are required/optional for uploaded photos. The initial system will not support admin customized attribute fields. However the system shall be designed so that it is open to adding this in the future.

    • VI.A.40.30 User Specified Attributes. The initial system will not support user customized attribute fields. However the system shall be designed so that it is open to adding user customized fields in the future.

  • VI.A.50 System shall be open to adding server-backed image manipulation with a future version. This may include image rotation, cropping, and other simple editing. Since image manipulation can be a cpu-intensive process, many users manipulating many images at the same time could potentially slow a sites response time. Any implementation of these feature should support redirecting manipulation requests to an alternate server for processing images to alleviate the load on the main server. Album Requirements

  • VI.B.10 Album is a group of 0 or more photos.

    • VI.B.10.10 Photos have a distinct order within an album

    • VI.B.10.20 User with edit privileges can modify/reorder photos within album.

  • VI.B.20 Album has page to display several thumbnail images in an album.

    • VI.B.20.10 Number of thumbnails per page is controlled in admin page. Display page must dynamically react to changes on the admin page.

    • VI.B.20.20 Thumbnail display can scroll through next and previous pages, next / previous page group, or click on page number.

    • VI.B.20.30 Clicking on thumbnail calls view-size display page.

    • VI.B.20.40 Attributes can be displayed with thumbnails. Display controlled in admin page or in template page.

  • VI.B.30 Album has page to display single view-size image.

    • VI.B.30.10 When viewing one image user can navigate to next and previous photo or return to thumbnail page.

    • VI.B.30.20 Viewer can display attributes of photo. Display controlled in admin page or in template page.

  • VI.B.40 The display pages should use templates for designating layout and formatting. The templates should be able to accommodate parameter changes made through the admin pages. So if the admin changes the albums from displaying 4 200x200 thumbnails at a time to 6 100x100 thumbnails, the display pages should reformat accordingly with minimal changes to the display templates

  • VI.B.50 Potential page to display the original images. Such a page would allow the user to view and save the original size high-resolution version of the photo instead of the lower resolution and smaller sized viewer and thumbnail images. Since some sites and admins may not want users to have access to the high-resolution originals, the admin must be able to toggle the availability of such page.

  • VI.B.60 User with edit privilege can do following:

    • VI.B.60.10 Upload new photos to an album and specify attributes during upload process.

    • VI.B.60.20 Photos can be moved to different albums within same hierarchy.

    • VI.B.60.30 Photos can be deleted from an album.

    • VI.B.60.40 Edit photo attribute information Album Hierarchy

  • VI.C.10 Albums can be grouped in a hierarchy of arbitrary depth.

  • VI.C.20 Display/sorting of hierarchy controlled on the page level but order field included to support arbitrary sorting.

  • VI.C.30 Admin (exact permission required, to be determined) can add/consolidate hierarchy levels.

  • VI.C.40 Admin (exact permission required, to be determined) can move items around in hierarchy.

  • VI.C.50 Admin (exact permission required, to be determined) can resrict the creation of new hierarchy levels. Administrative Control

  • VI.D.10 Number of thumbnail to be displayed at a time on the page described in VI.B.20 specified in by a sub-site admin. Number of thumbnails pre page can be changed by the admin at any time and display pages react accordingly.

  • VI.D.20 Thumbnail and view-size specified by sub-site admin.

    • VI.D.20.10 Thumbnail and view-size can be changed by sub-site-admin. Two options are allowed for size changes, proactive and retroactive.

      • VI.D.20.10.10 Proactive change will only change new photo uploads. Any changes will take affect immediately. Previously uploaded photos will maintain original thumbnail and view-size images until photo is revised.

      • VI.D.20.10.20 Retroactive changes will change new photo uploads and resize all previously uploaded photos. Since the time to complete such revision will vary with the number of photos uploaded, the system shall provides an estimate of how long it will take and asks if admin wishes to continue. If yes it schedule conversion process to run during low bandwidth times, and provides daily email updates if process will take longer than a day. Also checks for server crashes/restarts that would hinder conversion. (This requirement will be delayed until a future version)

  • VI.D.30 Admin can edit other people's albums.

  • VI.D.40 Admin designates default permissions for hierarchy levels. So various users can view, create, edit, and upload to different levels.

  • VI.D.50 Admin can allow user to access the page displaying the original size high-resolution version of a photo described in VI.B.50 Photo Upload

  • VI.E.10 Photos uploaded one at a time through an html form. Form shall provide ability to specify attribute information.

  • VI.E.20 Upload system shall support uploading to separate dedicated server(s). Creating the thumbnail and viewer size images of a photo can be a cpu-intensive process. Many users uploading many photos simultaneously can potentially slow a sites response time. Redirecting upload requests to an alternate server for processing images can lessen the load on the main server. (Implementation of this will be delayed until a future release).

  • VI.E.30 Future version to support bulk upload. General Requirements

  • VI.F.10 System to support sub-sites. Admin shall be able to add album implementation to multiple sub-sites on a web service.

  • VI.F.20 System shall be able to scale to at least the service level experienced by IluvCamp during summer 2000.

  • VI.F.30 Design to accommodate future integration of photo print and purchase capabilities as demonstrated on the IluvCamp Client sites. Requirements delayed until future version

  • VI.G.10 Purchase and printing of photo through ecommerce package and photo printing vendor.

  • VI.G.20 Server backed image manipulation

  • VI.G.30 Bulk upload tool

  • VI.G.40 User specified attributes

  • VI.G.50 Upload quotas

  • VI.G.60 Admin notification of file space limitations.

  • VI.G.70 Search and retrieval of photos and albums based on attributes or key words.

  • VI.G.80 Admin specified attributes

  • VI.G.90 Photo upload/manipulaion support for separate server.

4.1.7. Implementation Notes

A photo album system was built for the IluvCamp Client site. Much of the work on the ACS 4.0 Photo Album Package will be based on the lessons learned building and maintaining this system. Some of these lessons include:

  • The ability (and necessity on high volume sites) to support dedicated image processing servers. As outlined in two of the requirements above, numerous simultaneous image manipulations can tie up resources on the main server. Low volume sites may be able to handle image manipulation on the main server, but high volume sites will need the ability to pass these operations off to dedicated servers.

  • The ability to support a pool of multiple servers. The Iluvcamp site used a pool of multiple servers on several machines to support the high volumes of traffic. Additionally, many attributes of the album structure and hierarchy were cached to improve performance. When we made changes to these attributes that required cache flushes, we needed to make sure the caches were flushed on all the servers.

  • The Iluvcamp data structure mapped a specific number of images to a page and then mapped the pages to albums. All of this mapping and ordering information was stored in the database. This essentially hard-coded the image on page ordering and the number of images per page. Unfortunately this made changing the display of albums from 9 images per page to 4 images per page (a mid-season client request) time consuming and difficult. Given that the requirements allow for easy changes to the number of thumbnails displayed per page, such hard-coding should be avoided at all cost in the photo album package. Photos should be mapped directly to albums and pages within the album should be rendered dynamically.

  • The amount of time it takes to retroactively change thumbnail and view-size images. A client requested change of the thumbnail and viewer size images on IluvCamp took several weeks of processor time to modify ~ 240,000 previously uploaded images. Scheduling and monitoring the conversion process was a headache. We hope to figure out a easier way to make such a change.

4.1.8. Revision History

Document Revision #Action Taken, NotesWhen?By Whom?
0.1Creation, initial draft11/15/2000Tom Baginski
0.2Revisions in response to initial comments12/05/2000Tom Baginski
0.3Revisions in response to more comments12/11/2000Tom Baginski
0.4Minor revisions base on design experience2/2/2000Tom Baginski

Last Modified: $Date: 2017/05/26 18:05:37 $