Re: External File Model

There are different file-models that you can use with Magritte. The idea is that you set the #kind: of an MAFileDescription to one of the subclasses of MAFileModel. Earlier versions of Magritte used MAMemoryFileModel and kept all the data within a ByteArray in the memory. This is not really practicable for bigger files. MAMexternalFileModel tries to solve this problem. It manages the files on the file-system. From the programmer this looks the same as if the file would be in memory, as it is loaded and written out as necessary. - The #baseDirectory is the place where Magritte puts its file- database. Keep this value to nil to make it default to a subdirectory next to the Squeak image. (also check the method comment) - #baseUrl is a nice optimization to allow Apache (or any other Web Server) to directly serve the files. The #baseUrl is an absolute URL that is used to generate the path to the file. If you have one specified the file data does not go trough the image anymore, but instead is directly served trough the Web Server (assuming that you have a propre setup). Now you might wonder why the files are in directories like the following one? /files/9d/bsy8kyp45g0q7blphknk48zujap2wd/earthmap1k.jpg 1 2 3 4 (1) Is the #baseDirectory as specified in the settings. (2) Are 256 directories named '00' to 'FF' to avoid having thousands of files in the same directory. Unfortunately this leads to problems with the Squeak file primitives and some filesystems don't handle that well. This part is generated at random. (3) This is a secure id, similar to the Seaside session key. It is generated at random and provides sort of a security system that even works trough Apache (you have to disable directory listings of course): if you don't know the file-name you cannot access the file. (4) This is the original file-name. In the future there will be other cached versions of the file be stored there, for example resized images, etc. HTH, Lukas problems with filesystems and Squeak if there are thous So first of all -- Lukas Renggli http://www.lukas-renggli.ch