77 lines
1.6 KiB
Crystal
77 lines
1.6 KiB
Crystal
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# For now, upload and download are sequentials.
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# In a future version, we will be able to send
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# arbitrary parts of each file.
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# Who knows, maybe someday we will be on UDP, too.
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#class SHA256
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# JSON.mapping({
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# chunk: Slice(UInt8)
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# })
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#end
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module FileStorage
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# 1 MB read buffer, on-disk
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def self.file_reading_buffer_size
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1_000_000
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end
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# 1 KB message data buffer, on-network
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def self.message_buffer_size
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1_000
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end
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# private function
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def self.data_digest(data : Bytes)
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digest = OpenSSL::Digest.new "sha256"
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digest.update data
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digest.hexfinal
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end
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# private function
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def self.file_digest(file : File)
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# 1M read buffer
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buffer = Bytes.new(1_000_000)
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io = OpenSSL::DigestIO.new(file, "SHA256")
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while io.read(buffer) > 0 ; end
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io.digest.hexstring
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end
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end
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class FileStorage::Chunk
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include JSON::Serializable
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property n : Int32 # chunk's number
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property on : Int32 # number of chunks
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property digest : String # digest of the current chunk
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def initialize(@n, @on, data)
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@digest = FileStorage.data_digest data.to_slice
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end
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end
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# A file has a name, a size and tags.
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class FileStorage::FileInfo
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include JSON::Serializable
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property name : String
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property size : UInt64
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property nb_chunks : Int32
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property digest : String
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# list of SHA256, if we are on UDP
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# chunks: Array(SHA256),
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property tags : Array(String)
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def initialize(file : File, tags = nil)
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@name = File.basename file.path
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@size = file.size
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@digest = FileStorage.file_digest file
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@nb_chunks = (@size / FileStorage.message_buffer_size).ceil.to_i
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@tags = tags || [] of String
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end
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end
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