Can't Parse String in Ruby - ruby

I have the following string that I would like to split on the \xA7 character.
\xFF$New Server\xA77\xA750
The problem being is that I can't figure out how to tell Ruby to split it correctly on the \xA7 marker.
This is the error I get:
>> "\xFF$New Server\xA77\xA750".split("\xA7")
ArgumentError: invalid byte sequence in UTF-8
from (irb):26:in `split'
from (irb):26
from /Users/wedtm/.rbenv/versions/1.9.2-p290/bin/irb:12:in `<main>'

When forcing the encoding to BINARY you can work around that issue, though not sure if it's the correct solution or breaks other things...
input = "\xFF$New Server\xA77\xA750".force_encoding('BINARY')
split = "\xA7".force_encoding('BINARY')
input.split(split) # => ["\xFF$New Server", "7", "50"]

The problem is that the string has an invalid utf-8 byte sequence. If you don't care about that try putting this at the top of your document:
# coding: ascii

Related

How to make ruby indicate error before a binary function?

I have this code that works:
stripped = "00010001"
IO.binwrite("Test.txt", [stripped].pack('B*'))
But if stripped equals to:
stripped = "00013001"
Ruby writes the "binary" anyway. How can I make Ruby give me a mistake and not write it down?
"1000101010".scan(/[^01]/).any?
This simply performs a regex on the string looking for any characters that are not 0 or 1 and returns true if the string has any other characters.
The Integer method of Kernel accepts a base as argument and is strict (by default).
Integer("00011001",2).to_s(16)
# => "19"
Integer("00013001",2).to_s(16)
# => invalid value for Integer(): "00013001" (ArgumentError)

Ruby Cyphering Leads to non Alphanumeric Characters [duplicate]

This question already has answers here:
Rotating letters in a string so that each letter is shifted to another letter by n places
(4 answers)
Closed 5 years ago.
I'm trying to make a basic cipher.
def caesar_crypto_encode(text, shift)
(text.nil? or text.strip.empty? ) ? "" : text.gsub(/[a-zA-Z]/){ |cstr|
((cstr.ord)+shift).chr }
end
but when the shift is too high I get these kinds of characters:
Test.assert_equals(caesar_crypto_encode("Hello world!", 127), "eBIIL TLOIA!")
Expected: "eBIIL TLOIA!", instead got: "\xC7\xE4\xEB\xEB\xEE \xF6\xEE\xF1\xEB\xE3!"
What is this format?
The reason you get the verbose output is because Ruby is running with UTF-8 encoding, and your conversion has just produced gibberish characters (an invalid character sequence under UTF-8 encoding).
ASCII characters A-Z are represented by decimal numbers (ordinals) 65-90, and a-z is 97-122. When you add 127 you push all the characters into 8-bit space, which makes them unrecognizable for proper UTF-8 encoding.
That's why Ruby inspect outputs the encoded strings in quoted form, which shows each character as its hexadecimal number "\xC7...".
If you want to get some semblance of characters out of this, you could re-encode the gibberish into ISO8859-1, which supports 8-bit characters.
Here's what you get if you do that:
s = "\xC7\xE4\xEB\xEB\xEE \xF6\xEE\xF1\xEB\xE3!"
>> s.encoding
=> #<Encoding:UTF-8>
# Re-encode as ISO8859-1.
# Your terminal (and Ruby) is using UTF-8, so Ruby will refuse to print these yet.
>> s.force_encoding('iso8859-1')
=> "\xC7\xE4\xEB\xEB\xEE \xF6\xEE\xF1\xEB\xE3!"
# In order to be able to print ISO8859-1 on an UTF-8 terminal, you have to
# convert them back to UTF-8 by re-encoding. This way your terminal (and Ruby)
# can display the ISO8859-1 8-bit characters using UTF-8 encoding:
>> s.encode('UTF-8')
=> "Çäëëî öîñëã!"
# Another way is just to repack the bytes into UTF-8:
>> s.bytes.pack('U*')
=> "Çäëëî öîñëã!"
Of course the proper way to do this, is not to let the numbers overflow into 8-bit space under any circumstance. Your encryption algorithm has a bug, and you need to ensure that the output is in the 7-bit ASCII range.
A better solution
Like #tadman suggested, you could use tr instead:
AZ_SEQUENCE = *'A'..'Z' + *'a'..'z'
"Hello world!".tr(AZ_SEQUENCE.join, AZ_SEQUENCE.rotate(127).join)
=> "eBIIL tLOIA!
I'm still curious about that format though...
Those characters represent the corresponding ASCII encoding after getting the ordinal (ord) of each letter and adding 127 to it (i.e. (cstr.ord)+shift).chr)
Why? Check Integer#chr, from the docs:
Returns a string containing the character represented by the int's
value according to encoding.
So, for example, take your first letter "H":
char_ord = "H".ord
#=> 72
new_char_ord = char_ord + 127
#=> 199
new_char_ord.chr
#=> "\xC7"
So, 199 corresponds to "\xC7". Keep changing all characters in "Hello world" and you will get "\xC7\xE4\xEB\xEB\xEE \xF6\xEE\xF1\xEB\xE3".
To avoid this you need to loop only with ord values that represent a letter (answer in the Possible duplicate link).

Convert from ISO-2022-JP-2 to UTF-8 in Ruby 2.1

I have a ISO-2022-JP-2 string and need to convert it to UTF-8, but I am getting an error.
To be more concrete: I am trying to read an email which is transferred using quoted-printable. This email contains the word tōtatsu (notice the accent above the o) and I am converting the given text like this:
given = "t=1B$(D+W=1B(Btatsu"
text = given.unpack("M*").first #convert from quoted-printable
Basically this will replace =1B with the proper \e escape character and the string in text becomes t␛$(D+W␛(Btatsu.
Wikipedia says that ␛$(D is used to switch to JIS X 0212-1990 and likewise ␛(B is used to switch back to ASCII. Notice that ␛$(D is new in ISO-2022-JP-2, it is not part of the original ISO-2022-JP.
However, the encoding of the string is still ASCII, so I guess I have to force the proper encoding since Ruby has no way of knowing that the actual string is ISO-2022-JP-2?
puts text.encoding # ASCII-8BIT
text = text.force_encoding('iso-2022-jp-2')
Now it turns out that
text.encode('utf-8')
is not able to convert the given string: code converter not found (ISO-2022-JP-2 to UTF-8) (Encoding::ConverterNotFoundError)
How can I convert this string to UTF-8?
It seems like Ruby 2.1 does not support iso-2022-jp-2 encoding:
>> "t\e$(D+W\e(Btatsu".encode('utf-8', 'iso-8859-1')
=> "t\e$(D+W\e(Btatsu"
>> "t\e$(D+W\e(Btatsu".encode('utf-8', 'iso-2022-jp-2')
Encoding::ConverterNotFoundError: code converter not found (ISO-2022-JP-2 to UTF-8)
from (irb):1:in `encode'
from (irb):1
from /home/falsetru/.rvm/rubies/ruby-2.1.2/bin/irb:11:in `<main>'
You can use iconv instead:
require 'iconv'
Iconv.conv('utf-8', 'iso-2022-jp-2', "t\e$(D+W\e(Btatsu")
# => "tōtatsu"

Encoding::UndefinedConversionError

I keep getting an Encoding::UndefinedConversionError - "\xC2" from ASCII-8BIT to UTF-8 every time I try to convert a hash into a JSON string. I tried with [.encode | .force_encoding](["UTF-8" | "ASCII-8BIT" ]), chaining .encode with .force_encoding, backwards, switching parameters but nothing seemed to work so I caught the error like this:
begin
menu.to_json
rescue Encoding::UndefinedConversionError
puts $!.error_char.dump
p $!.error_char.encoding
end
Where menu is a sequel's dataset.to_hash with content from a MySQL DB, utf8_general_ci encoding and returned this:
"\xC2"
<#Encoding:ASCII-8BIT>
The encoding never changes, no matter what .encode/.force_encoding I use. I've even tried to replace the string .gsub!(/\\\xC2/) without luck.
Any ideas?
menu.to_s.encode('UTF-8', invalid: :replace, undef: :replace, replace: '?')
This worked perfectly, I had to replace some extra characters but there are no more errors.
What do you expect for "\xC2"? Probably a Â
With ASCII-8BIT you have binary data, and ruby cant decide, what should be.
You must first set the encoding with force_encoding.
You may try the following code:
Encoding.list.each{|enc|
begin
print "%-10s\t" % [enc]
print "\t\xC2".force_encoding(enc)
print "\t\xC2".force_encoding(enc).encode('utf-8')
rescue => err
print "\t#{err}"
end
print "\n"
}
The result are the possible values in different encodings for your "\xC2".
The result may depend on your Output format, but I think you can make a good guess, which encoding you have.
When you defined the encoding you need (probably cp1251) you can
menu.force_encoding('cp1252').to_json
See also Kashyaps comment.
If you don't care about losing the strange characters, you can blow them away:
str.force_encoding("ASCII-8BIT").encode('UTF-8', undef: :replace, replace: '')
Your auto-accepted solution doesn't work, there are effectively no errors, but it is NOT JSON.
I solved the problem using the oj gem, it now works find. It is also faster than the standard JSON library.
Writting :
menu_json = Oj.dump menu
Reading :
menu2 = Oj.load menu_json
https://github.com/ohler55/oj for more details. I hope it will help.
:fallback option can be useful if you know what chars you want to replace
"Text 🙂".encode("ASCII", "UTF-8", fallback: {"🙂" => ":)"})
#=> hello :)
From docs:
Sets the replacement string by the given object for undefined character. The object should be a Hash, a Proc, a Method, or an object which has [] method. Its key is an undefined character encoded in the source encoding of current transcoder. Its value can be any encoding until it can be converted into the destination encoding of the transcoder.

when we import csv data, how eliminate "invalid byte sequence in UTF-8"

we allow users to import data via csv (using ruby 1.9.2, hence it's fastercsv).
being user data, of course, it might not be properly sanitized.
When we try to display the data in an /index method we sometimes get the error "invalid byte sequence in UTF-8" pointing to our erb where we display one of the fields widget.name
When we do the import we'd like to FORCE the incoming data to be valid... is there a ruby operator that will map a string to a valid utf8 string, eg, something like
goodstring = badstring.no_more_invalid_bytes
One example of 'bad' data is char that looks like a hyphen but is not a regular ascii hyphen. We'd prefer to map the non-utf-8 chars to a reasonable ascii equivalent (umlat-u going to u for exmaple) BUT we're okay with simply stripping the character to.
since this is when importing lots of data, it needs to be a fast built-in operator, hopefully...
Note: here is an example of the data. The file comes form windows and is 8bit ascii. when we import it and in our erb we display widget.name.inspect (instead of widget.name) we get:
"Chains \x96 Accessories"
so one example of the data is a "hyphen" that's actually 8 bit code 96.
--- when we changed our csv parse to assign fldval = d.encode('UTF-8')
it throws this error:
Encoding::UndefinedConversionError in StoresController#importfinderitems
"\x96" from ASCII-8BIT to UTF-8
what we're looking for is a simple way to just force it to be valid utf8 regardless of origin type, even if we simply strip non-ascii.
while not as 'nice' as forcing the encoding, this works at a slight expense to our import time:
d.to_s.strip.gsub(/\P{ASCII}/, '')
Thank you, Mladen!
Ruby 1.9 CSV has new parser that works with m17n. The parser works with Encoding of IO object in the string. Following methods: ::foreach, ::open, ::read, and ::readlines could take in optional options :encoding which you could specify the the Encoding.
For example:
CSV.read('/path/to/file', :encoding => 'windows-1251:utf-8')
Would convert all strings to UTF-8.
Also you can use the more standard encoding name 'ISO-8859-1'
CSV.read('/..', {:headers => true, :col_sep => ';', :encoding => 'ISO-8859-1'})
CSV.parse(File.read('/path/to/csv').scrub)
I answered a similar question that deals with reading external files in 1.9.2 with non-UTF-8 encodings. I think that answer will help you a lot: Character Encoding issue in Rails v3/Ruby 1.9.2
Note that you need to know the source encoding for you to convert it anything reliably. There are libraries like the one I linked to in my other answer that can help you determine this.
Also, if you aren't loading the data from a file, you can convert the encoding of a string in 1.9.2 quite easily:
'string'.encode('UTF-8')
However, it's rare that you're building a string in another encoding, and it's best to convert it at the time it's read into your environment if possible.
Ruby 1.9 can change string encoding with invalid detection and replacement:
str = str.encode('UTF-8', :invalid => :replace)
For unusual strings such as strings loaded from a file of unknown encoding, it's wise to use #encode instead of a regex, #gsub, or #delete, because these all need the string to be parsed-- but if the string is broken, it can't be parsed, so those methods fail.
If you get a message like this:
error ** from ASCII-8BIT to UTF-8
Then you're probably trying to convert a binary string that's already in UTF-8, and you can force UTF-8:
str.force_encoding('UTF-8')
If you know the original string is not in binary UTF-8, or if the output string has illiegal characters, then read up on Ruby encoding transliterations.
If you are using Rails, you can try to fix it with the following
'Your string with strange stuff ##~'.mb_chars.tidy_bytes
It removes you the invalid utf-8 chars and replaces it with valid ones.
More info: https://apidock.com/rails/String/mb_chars
Upload the CSV file to Google Docs Spreadsheet and re-download it as a CSV file. Import and voila! (Worked in my case)
Presumably Google converts it to the wanted format..
Source: Excel to CSV with UTF-8 Encoding
As mentioned by someone else, scrub works well to clean this up in Ruby 2.1+. If you have a large file you may not want to read the whole thing into memory, so you can use scrub like this:
data = IO::read(file_path).scrub("")
CSV.parse(data, :col_sep => ',', :headers => true) do |row|
puts row
end
I am using MAC and I was having the same error:
rescue in parse:Invalid byte sequence in UTF-8 in line 1 (CSV::MalformedCSVError)
I added :encoding => 'ISO-8859-1' that resolved my error and csv file could be read.
results = CSV.read("query_result.csv",{:headers => true, :encoding => 'ISO-8859-1'})
:headers => true : If set to :first_row or true, the initial row of the CSV file will be treated as a row of headers. If set to an Array, the contents will be used as the headers. If set to a String, the String is run through a call of ::parse_line with the same :col_sep, :row_sep, and :quote_char as this instance to produce an Array of headers. This setting causes #shift to return rows as CSV::Row objects instead of Arrays and #read to return CSV::Table objects instead of an Array of Arrays.
irb(main):024:0> rows = CSV.new(StringIO.new("a,b,c\n1,2,3"), headers: true)
=> <#CSV io_type:StringIO encoding:UTF-8 lineno:0 col_sep:"," row_sep:"\n" quote_char:"\"" headers:true>
irb(main):025:0> rows = CSV.new(StringIO.new("a,b,c\n1,2,3"), headers: true).to_a
=> [#<CSV::Row "a":"1" "b":"2" "c":"3">]
irb(main):026:0> rows.first['a']
=> "1"
In above example you can clearly see that this also enables us to use data as hashes.
The only thing you would need to be careful about while using headers: true that it won't allow any duplicate headers as keys are unique in hashes.
Only do this
anyobject.to_csv(:encoding => 'utf-8')

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