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81723d55ac
TRUE and FALSE are keywords whereas T and F are just predefined variables that can be reassigned
96 lines
2.7 KiB
R
96 lines
2.7 KiB
R
# For HTML5-capable browsers, file uploads happen through a series of requests.
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#
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# 1. Client tells server that one or more files are about to be uploaded; the
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# server responds with a "job ID" that the client should use for the rest of
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# the upload.
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#
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# 2. For each file (sequentially):
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# a. Client tells server the name, size, and type of the file.
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# b. Client sends server a small-ish blob of data.
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# c. Repeat 2b until the entire file has been uploaded.
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# d. Client tells server that the current file is done.
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#
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# 3. Repeat 2 until all files have been uploaded.
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#
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# 4. Client tells server that all files have been uploaded, along with the
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# input ID that this data should be associated with.
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#
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# Unfortunately this approach will not work for browsers that don't support
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# HTML5 File API, but the fallback approach we would like to use (multipart
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# form upload, i.e. traditional HTTP POST-based file upload) doesn't work with
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# the websockets package's HTTP server at the moment.
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FileUploadOperation <- setRefClass(
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'FileUploadOperation',
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fields = list(
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.parent = 'ANY',
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.id = 'character',
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.files = 'data.frame',
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.dir = 'character',
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.currentFileInfo = 'list',
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.currentFileData = 'ANY'
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),
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methods = list(
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initialize = function(parent, id, dir) {
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.parent <<- parent
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.id <<- id
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.dir <<- dir
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},
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fileBegin = function(file) {
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.currentFileInfo <<- file
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filename <- file.path(.dir, as.character(length(.files)))
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row <- data.frame(name=file$name, size=file$size, type=file$type,
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datapath=filename, stringsAsFactors=FALSE)
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if (length(.files) == 0)
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.files <<- row
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else
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.files <<- rbind(.files, row)
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.currentFileData <<- file(filename, open='wb')
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},
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fileChunk = function(rawdata) {
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writeBin(rawdata, .currentFileData)
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},
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fileEnd = function() {
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close(.currentFileData)
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},
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finish = function() {
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.parent$onJobFinished(.id)
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return(.files)
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}
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)
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)
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FileUploadContext <- setRefClass(
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'FileUploadContext',
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fields = list(
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.basedir = 'character',
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.operations = 'Map'
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),
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methods = list(
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initialize = function(dir=tempdir()) {
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.basedir <<- dir
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},
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createUploadOperation = function() {
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while (TRUE) {
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id <- paste(as.raw(runif(12, min=0, max=0xFF)), collapse='')
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dir <- file.path(.basedir, id)
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if (!dir.create(dir))
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next
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op <- FileUploadOperation$new(.self, id, dir)
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.operations$set(id, op)
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return(id)
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}
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},
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getUploadOperation = function(jobId) {
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.operations$get(jobId)
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},
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onJobFinished = function(jobId) {
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.operations$remove(jobId)
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}
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)
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)
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