wekan/packages/wekan-cfs-temp-store/api.md

cfs-tempstore Public API

CollectionFS, temporary storage

API documentation automatically generated by docmeteor.

##Temporary Storage

Temporary storage is used for chunked uploads until all chunks are received and all copies have been made or given up. In some cases, the original file is stored only in temporary storage (for example, if all copies do some manipulation in beforeSave). This is why we use the temporary file as the basis for each saved copy, and then remove it after all copies are saved.

Every chunk is saved as an individual temporary file. This is safer than attempting to write multiple incoming chunks to different positions in a single temporary file, which can lead to write conflicts.

Using temp files also allows us to easily resume uploads, even if the server restarts, and to keep the working memory clear.

The FS.TempStore emits events that others are able to listen to

fs.TempStore {object}  _Server

This property TempStore is defined in FS it's an event emitter*

FS.TempStore = new EventEmitter(); tempStore.js:28

- We will not mount a storage adapter until needed. This allows us to check for the existance of FS.FileWorker, which is loaded after this package because it depends on this package.

- XXX: TODO FS.TempStore.on('stored', function(fileObj, chunkCount, result) { This should work if we pass on result from the SA on stored event... fileObj.update({ $set: { chunkSum: 1, chunkCount: chunkCount, size: result.size } }); });

Stream implementation

fsTempstore.removeFile(fileObj)  _Server

This method removeFile is defined in FS.TempStore

Arguments

• fileObj {FS.File}
  

This function removes the file from tempstorage - it cares not if file is already removed or not found, goal is reached anyway.

FS.TempStore.removeFile = function(fileObj) { ... tempStore.js:169

-

fsTempstore.createWriteStream(fileObj, [options])  _Server

This method createWriteStream is defined in FS.TempStore

Arguments

• fileObj {FS.File}
  

File to store in temporary storage

• options {Number | String} (Optional)

Returns {Stream} Writeable stream

options of different types mean differnt things: undefined We store the file in one part (Normal server-side api usage)* Number the number is the part number total (multipart uploads will use this api)* String the string is the name of the store that wants to store file data (stores that want to sync their data to the rest of the files stores will use this)*

Note: fileObj must be mounted on a FS.Collection, it makes no sense to store otherwise

FS.TempStore.createWriteStream = function(fileObj, options) { ... tempStore.js:217

-

fsTempstore.createReadStream(fileObj)  _Server

This method createReadStream is defined in FS.TempStore

Arguments

• fileObj {FS.File}
  

The file to read

Returns {Stream} Returns readable stream

FS.TempStore.createReadStream = function(fileObj) { ... tempStore.js:313