I am able to access the binary data of a file and store it in a varible like this
s = File.binread("sample_22122015_03.jpg")
bits = s.unpack("B*")[0]
where bits has data like this "101001001010100100......."
However, I want to do some changes and again write the binary data back to a new image, but I am unable to.
I am using
File.open('shipping_label_new.jpg', 'wb') do|f|
f.write(Base64.decode64(bits))
end
but it's not working and I see that the image is corrupt.
Try this code
s = File.binread("test_img.jpg")
bits = s.unpack("B*")
File.open('new_test_img.jpg', 'wb') do|f|
f.write(bits.pack("B*"))
end
The reverse of String.unpack is Array.pack:
:007 > bits = 'abc'.unpack("B*")
=> ["011000010110001001100011"]
:008 > bits.pack("B*")
=> "abc"
Related
I want to upload data binary directly to GCP storage, without writing the file to disk. Below is the code snippet I have created to get to the state that I am going to be at.
require 'google/cloud/storage'
bucket_name = '-----'
data = File.open('image_block.jpg', 'rb') {|file| file.read }
storage = Google::Cloud::Storage.new("project_id": "maybe-i-will-tell-u")
bucket = storage.bucket bucket_name, skip_lookup: true
Now I want to directly put this data into a file on gcs, without having to write a file to disk.
Is there an efficient way we can do that?
I tried the following code
to_send = StringIO.new(data).read
bucket.create_file to_send, "image_inder_11111.jpg"
but this throws an error saying
/google/cloud/storage/bucket.rb:2898:in `file?': path name contains null byte (ArgumentError)
from /home/inder/.gem/gems/google-cloud-storage-1.36.1/lib/google/cloud/storage/bucket.rb:2898:in `ensure_io_or_file_exists!'
from /home/inder/.gem/gems/google-cloud-storage-1.36.1/lib/google/cloud/storage/bucket.rb:1566:in `create_file'
from champa.rb:14:in `<main>'
As suggested by #stefan, It should be to_send = StringIO.new(data), i.e. without .read (which would return a string again)
I'm trying to test the size of an upload to validate its size. Outside of the upload algos, simply looking at the temp file is where I'm having the issue. I have a test file on my desktop named test1.png, which is 115 KB.
a = '/users/rich/desktop/test1.png'
s = File.open(a, 'wb')
r = File.size(a)
p r => 0
p s.size => 0
Not sure what I'm doing wrong here, but both resolve to 0. Not true.
How can I get the size of a file?
The problem is the 'w' flag, since it truncates existing file to zero length, so, since you open the file before getting its size, you get 0.
To get the size you could just use the path of the file without using File.open:
a = '/users/rich/desktop/test1.png'
File.size(a)
Or, if you need to create the File object, just use the 'r' flag:
a = '/users/rich/desktop/test1.png'
s = File.open(a, 'r')
Now you can either use File.size(a) or s.size to get the size of the file.
I'm having difficulty to Encrypt large files (bigger than available memory) using GPGME in Ruby.
#!/usr/bin/ruby
require 'gpgme'
def gpgfile(localfile)
crypto = GPGME::Crypto.new
filebasename = File.basename(localfile)
filecripted = crypto.encrypt File.read(localfile), :recipients => "info#address.com", :always_trust => true
File.open("#{localfile}.gpg", 'w') { |file| file.write(filecripted) }
end
gpgpfile("/home/largefile.data")
In this case I got an error of memory allocation:
"read: failed to allocate memory (NoMemoryError)"
Someone can explain me how to read the source file chunk by chunk (of 100Mb for example) and write them passing by the crypting?
The most obvious problem is that you're reading the entire file into memory with File.read(localfile). The Crypto#encrypt method will take an IO object as its input, so instead of File.read(localfile) (which returns the contents of the file as a string) you can pass it a File object. Likewise, you can give an IO object as the :output option, letting you write the output directly to a file instead of in memory:
def gpgfile(localfile)
infile = File.open(localfile, 'r')
outfile = File.open("#{localfile}.gpg", 'w')
crypto = GPGME::Crypto.new
crypto.encrypt(infile, recipients: "info#address.com",
output: outfile,
always_trust: true)
ensure
infile.close
outfile.close
end
I've never used ruby-gpgme, so I'm not 100% sure this will solve your problem since it depends a bit on what ruby-gpgme does behind the scenes, but from the docs and the source I've peeked at it seems like a sanely-built gem so I'm guessing this will do the trick.
I am trying to save compressed strings to a file and load them later for use in the game. I kept getting "in 'finish': buffer error" errors when loading the data back up for use. I came up with this:
require "zlib"
def deflate(string)
zipper = Zlib::Deflate.new
data = zipper.deflate(string, Zlib::FINISH)
end
def inflate(string)
zstream = Zlib::Inflate.new
buf = zstream.inflate(string)
zstream.finish
zstream.close
buf
end
setting = ["nothing","nada","nope"]
taggedskills = ["nothing","nada","nope","nuhuh"]
File.open('testzip.txt','wb') do |w|
w.write(deflate("hello world")+"\n")
w.write(deflate("goodbye world")+"\n")
w.write(deflate("etc")+"\n")
w.write(deflate("etc")+"\n")
w.write(deflate("Setting: name "+setting[0]+" set"+(setting[1].class == String ? "str" : "num")+" "+setting[1].to_s)+"\n")
w.write(deflate("Taggedskill: "+taggedskills[0]+" "+taggedskills[1]+" "+taggedskills[2]+" "+taggedskills[3])+"\n")
w.write(deflate("etc")+"\n")
end
File.open('testzip.txt','rb') do |file|
file.each do |line|
p inflate(line)
end
end
It was throwing errors at the "Taggedskill:" point. I don't know what it is, but trying to change it to "Skilltag:", "Skillt:", etc. continues to throw a buffer error, while things like "Setting:" or "Thing:" work fine, while changing the setting line to "Taggedskill:" continues to work fine. What is going on here?
In testzip.txt, you are storing newline separated binary blobs. However, binary blobs may contain newlines by themselves, so when you open testzip.txt and split it by line, you may end up splitting one binary blob that inflate would understand, into two binary blobs that it does not understand.
Try to run wc -l testzip.txt after you get the error. You'll see the file contains one more line, than the number of lines you are putting in.
What you need to do, is compress the whole file at once, not line by line.
Is there a way to remove the BOM from a UTF-8 encoded file?
I know that all of my JSON files are encoded in UTF-8, but the data entry person who edited the JSON files saved it as UTF-8 with the BOM.
When I run my Ruby scripts to parse the JSON, it is failing with an error.
I don't want to manually open 58+ JSON files and convert to UTF-8 without the BOM.
With ruby >= 1.9.2 you can use the mode r:bom|utf-8
This should work (I haven't test it in combination with json):
json = nil #define the variable outside the block to keep the data
File.open('file.txt', "r:bom|utf-8"){|file|
json = JSON.parse(file.read)
}
It doesn't matter, if the BOM is available in the file or not.
Andrew remarked, that File#rewind can't be used with BOM.
If you need a rewind-function you must remember the position and replace rewind with pos=:
#Prepare test file
File.open('file.txt', "w:utf-8"){|f|
f << "\xEF\xBB\xBF" #add BOM
f << 'some content'
}
#Read file and skip BOM if available
File.open('file.txt', "r:bom|utf-8"){|f|
pos =f.pos
p content = f.read #read and write file content
f.pos = pos #f.rewind goes to pos 0
p content = f.read #(re)read and write file content
}
So, the solution was to do a search and replace on the BOM via gsub!
I forced the encoding of the string to UTF-8 and also forced the regex pattern to be encoded in UTF-8.
I was able to derive a solution by looking at http://self.d-struct.org/195/howto-remove-byte-order-mark-with-ruby-and-iconv and http://blog.grayproductions.net/articles/ruby_19s_string
def read_json_file(file_name, index)
content = ''
file = File.open("#{file_name}\\game.json", "r")
content = file.read.force_encoding("UTF-8")
content.gsub!("\xEF\xBB\xBF".force_encoding("UTF-8"), '')
json = JSON.parse(content)
print json
end
You can also specify encoding with the File.read and CSV.read methods, but you don't specify the read mode.
File.read(path, :encoding => 'bom|utf-8')
CSV.read(path, :encoding => 'bom|utf-8')
the "bom|UTF-8" encoding works well if you only read the file once, but fails if you ever call File#rewind, as I was doing in my code. To address this, I did the following:
def ignore_bom
#file.ungetc if #file.pos==0 && #file.getc != "\xEF\xBB\xBF".force_encoding("UTF-8")
end
which seems to work well. Not sure if there are other similar type characters to look out for, but they could easily be built into this method that can be called any time you rewind or open.
Server side cleanup of utf-8 bom bytes that worked for me:
csv_text.gsub!("\xEF\xBB\xBF".force_encoding(Encoding::BINARY), '')