How can I load a YAML file regardlessly of its encoding?
My YAML file can be encoded in UTF-8 or ANSI (that's what Notepad++ calls it - I guess it's Windows-1252):
:key1:
:key2: "ä"
utf8.yml is encoded in UTF-8, ansi.yml is encoded in ANSI. I load the files as follows:
# encoding: utf-8
Encoding.default_internal = "utf-8"
utf8_load = YAML::load(File.open('utf8.yml'))
utf8_load_file = YAML::load_file('utf8.yml')
ansi_load = YAML::load(File.open('ansi.yml'))
ansi_load_file = YAML::load_file('ansi.yml')
It seems like Ruby doesn't recognize the encoding correctly:
utf8_load [:key1][:key2].encoding #=> "UTF-8"
utf8_load_file [:key1][:key2].encoding #=> "UTF-8"
ansi_load [:key1][:key2].encoding #=> "UTF-8"
ansi_load_file [:key1][:key2].encoding #=> "UTF-8"
because the bytes aren't the same:
utf8_load [:key1][:key2].bytes #=> [195, 164]
utf8_load_file [:key1][:key2].bytes #=> [195, 164]
ansi_load [:key1][:key2].bytes #=> [239, 191, 189]
ansi_load_file [:key1][:key2].bytes #=> [239, 191, 189]
If I miss Encoding.default_internal = "utf-8", the bytes are also different:
utf8_load [:key1][:key2].bytes #=> [195, 131, 194, 164]
utf8_load_file [:key1][:key2].bytes #=> [195, 164]
ansi_load [:key1][:key2].bytes #=> [195, 164]
ansi_load_file [:key1][:key2].bytes #=> [239, 191, 189]
What happens actually when I don't set the default_internal to utf-8?
Which encodings do the strings in both examples have?
How can I load a file even if I don't know its encoding?
I believe officially YAML only supports UTF-8 (and maybe UTF-16). There have historically been all sorts of encoding confusions in YAML libraries. I think you are going to run into trouble trying to have YAML in something other than a Unicode encoding.
What happens actually when I don't set the default_internal to utf-8?
Encoding.default_internal controls the encoding your input will be converted to when it is read in, at least by some operations that respect Encoding.default_internal, not everything does. Rails seems to set it to UTF-8. So if you don't set the Encoding.default_internal to UTF-8, it might be UTF-8 already anyway.
If Encoding.default_internal is nil, then those operations that respect it, and try to convert any input to Encoding.default_internal upon reading it in won't do that, they'll leave any input in the encoding it was believed to originate in, not try to convert it.
If you set it to something else, like say "WINDOWS-1252" Ruby would automatically convert your stuff to WINDOWS-1252 when it read it in with File.open, which would possibly confuse YAML::load when you pass the string that's now encoded and tagged as WINDOWS-1252 to it. Generally there's no good reason to do this, so leave Encoding.default_internal alone.
Note: The Ruby docs say:
"You should not set ::default_internal in Ruby code as strings created before changing the value may have a different encoding from strings created after the change. Instead you should use ruby -E to invoke Ruby with the correct default_internal."
See also: http://ruby-doc.org/core-1.9.3/Encoding.html#method-c-default_internal
Which encodings do the strings in both examples have?
I don't really know. One would have to have to look at the bytes and try to figure out if they are legal bytes for various plausible encodings, and beyond being legal, if they mean something likely to be intended.
For example take: "ÉGÉìÉRÅ[ÉfÉBÉìÉOÇÕìÔǵÇ≠ǻǢ". That's a perfectly legal UTF-8 string, but as humans we know it's probably not intended, and is probably garbage, quite likely from the result of an encoding misinterpretation. But a computer has no way to know that, it's perfectly legal UTF-8, and, hey, maybe someone actually did mean to write "ÉGÉìÉRÅ[ÉfÉBÉìÉOÇÕìÔǵÇ≠ǻǢ", after all, I just did, when writing this post!
So you can try to interpret the bytes according to various encodings and see if any of them make sense.
You're really just guessing at this point. Which means...
How can I load a file even if I don't know it's encoding?
Generally, you can not. You need to know and keep track of encodings. There's no real way to know what the bytes mean without knowing their encoding.
If you have some legacy data for which you've lost this, you've got to try to figure it out. Manually, or with some code that tries to guess likely encodings based on heuristics. Here's one Ruby gem Charlock Holmes that tries to guess, using the ICU library heuristics (this particular gem only works on MRI).
What Ruby says in response to string.encoding is just the encoding the string is tagged with. The string can be tagged with the wrong encoding, the bytes in the string don't actually mean what is intended in the encoding it's tagged with... in which case you'll get garbage.
Ruby will do the right things with your string instead of creating garbage only if the string's encoding tag is correct. The string's encoding tag is determined by Encoding.default_external for most input operations by default (Encoding.default_external usually starts out as UTF-8, or ASCII-8BIT which really means the null encoding, binary data, not tagged with an encoding), or by passing an argument to File.open: File.open("something", "r:UTF-8" or, means the same thing, File.open("something", "r", :encoding => "UTF-8"). The actual bytes are determined by whatever is in the file. It's up to you to tell Ruby the correct encoding to interpret those bytes as text meaning what they were intended to mean.
There were a couple posts recently to reddit /r/ruby that try to explain how to troubleshoot and workaround encoding issues that you may find helpful:
http://www.justinweiss.com/articles/how-to-get-from-theyre-to-theyre/
http://www.justinweiss.com/articles/3-steps-to-fix-encoding-problems-in-ruby/
Also, this is my favorite article on understanding encoding generally: http://kunststube.net/encoding/
For YAML files in particular, if I were you, I'd just make sure they are all in UTF-8. Life will be much easier and you won't have to worry about it. If you have some legacy ones that have become corrupted, it's going to be a pain to fix them, but that's what you've got to do, unless you can just rewrite them from scratch. Try to fix them to be in valid and correct UTF-8, and from here on out keep all your YAML in UTF-8.
The YAML specification says in "5.1. Character Set":
To ensure readability, YAML streams use only the printable subset of the Unicode character set. The allowed character range explicitly excludes the C0 control block #x0-#x1F (except for TAB #x9, LF #xA, and CR #xD which are allowed), DEL #x7F, the C1 control block #x80-#x9F (except for NEL #x85 which is allowed), the surrogate block #xD800-#xDFFF, #xFFFE, and #xFFFF.
This means that Windows-1252 or ISO-8859-1 encoding are acceptable as long as the characters being output are within the defined range. Windows users tend to use the "the C1 control block #x80-#x9F" range for diacritical and accented characters, so if those are present in a YAML file the file is not going to meet the spec and the YAML generator didn't do its job correctly. And that explains why "ä" isn't acceptable.
On output, a YAML processor must only produce acceptable characters. Any excluded characters must be presented using escape sequences. In addition, any allowed characters known to be non-printable should also be escaped. This isn’t mandatory since a full implementation would require extensive character property tables.
These days, by default, Ruby uses UTF-8, however YAML isn't limited to that. The spec goes on to say in "5.2. Character Encodings":
On input, a YAML processor must support the UTF-8 and UTF-16 character encodings. For JSON compatibility, the UTF-32 encodings must also be supported.
If a character stream begins with a byte order mark, the character encoding will be taken to be as as indicated by the byte order mark. Otherwise, the stream must begin with an ASCII character. This allows the encoding to be deduced by the pattern of null (#x00) characters.
So, UTF-8, 16 and 32 are supported, but Ruby will assume UTF-8. If the BOM is present you'll see it when you view the file in an editor. I haven't tried loading a UTF-16 or 32 file to see what Ruby's YAML does, so that's left as an experiment.
Related
According to it's source code https://www.rubydoc.info/stdlib/core/Integer:chr, this method uses ASCII encoding if no arguments provided, and really, it gives different results when called with and without arguments:
irb(main):002:0* 255.chr
=> "\xFF"
irb(main):003:0' 255.chr 'utf-8'
=> "ÿ"
Why does this happen? Isn't Ruby supposed to use UTF-8 everywhere by default? At least all strings seem to be encoded with UTF-8:
irb(main):005:0> "".encoding
=> #<Encoding:UTF-8>
Why does this happen?
For characters from U+0000 to U+007F (127), the vast majority of single-octet and variable-length character encodings agree on the encoding. In particular, they all agree on being strict supersets of ASCII.
In other words: for characters up to and including U+007F, ASCII, the entire ISO8859 family, the entire DOS codepage family, the entire Windows family, as well as UTF-8 are actually identical. So, for characters between U+0000 and U+007F, ASCII is the logical choice:
0.chr.encoding
#=> #<Encoding:US-ASCII>
127.chr.encoding
#=> #<Encoding:US-ASCII>
However, for anything above 127, more or less no two character encodings agree. In fact, the overwhelming majority of characters above 127 don't even exist in the overwhelming majority of characters sets, thus don't have an encoding in the vast majority of character encodings.
In other words: it is practically impossible to find a single default encoding for characters above 127.
Therefore, the encoding that is chosen by Ruby is Encoding::BINARY, which is basically a pseudo-encoding that means "this isn't actually text, this is unstructured unknown binary data". (For hysterical raisins, this encoding is also aliased to ASCII-8BIT, which I find absolutely horrible, because ASCII is 7 bit, period, and anything using the 8th bit is by definition not ASCII.)
128.chr.encoding
#=> #<Encoding:ASCII-8BIT>
255.chr.encoding
#=> #<Encoding:ASCII-8BIT>
Note also that Integer#chr is limited to a single octet, i.e. to a range from 0 to 255, so multi-octet or variable-length encodings are not really required here.
Isn't Ruby supposed to use UTF-8 everywhere by default?
Which encoding are you talking about? Ruby has about a half dozen of them.
For the vast majority of encodings, your statement is incorrect.
the locale encoding is the default encoding of the environment
the filesystem encoding is the encoding that is used for file paths: the value is determined by the file system
the external encoding of an IO object is the encoding that text that this read is assumed to be in and text that is written is transcoded to: the default is the locale encoding
the internal encoding of an IO object is the encoding that Strings that are written to the IO object must be in and that Strings that are read from the IO object are transcoded into: the default is the default internal encoding, whose default value, in turn, is nil, meaning no transcoding occurs
the script encoding is the encoding that a Ruby script is read, and also String literals in the script will inherit this encoding: it is set with a magic comment at the beginning of the script, and the default is UTF-8
So, as you can see, there are many different encodings, and many different defaults, and only one of them is UTF-8. And none of those encodings are actually relevant to your question, because 128.chr is neither a String literal nor an IO object. It is a String object that is created by the Integer#chr method using whatever encoding it sees fit.
How to keep all characters converting from UTF-8 to CP1252 on ruby 2.2
this code:
file = 'd:/1 descrição.txt'
puts file.encode('cp1252')
Give this error:
`encode': U+0327 to WINDOWS-1252 in conversion from UTF-8 to WINDOWS-1252 (Encoding::UndefinedConversionError)
My application need to be cp1252, but I can't find any way to keep all the characters.
I can't replace this characters, because later I will use this info to read the file from file system.
puts file.encode('cp1252', undef: :replace, replace: '')
> d:/1 descricao.txt
ps: It is a ruby script not a ruby on rails application
UTF-8 covers the entire range of unicode, but CP1252 only includes a subset of them. Obviously this means that there are characters that can be encoded in UTF-8 but not in CP1252. This is the problem you are facing.
In your example it looks like the string only contains characters that should work in CP1252, but clearly it doesn’t.
The character in the error message, U+0327 is a combining character, and is not representable in CP1252. It combines with the preceding c to produce ç. ç can also be represented as a single character (U+00E7), which is representable in CP1252.
One option might be normalisation, which will convert the string into a form that is representable in CP1252.
file = 'd:/1 descrição.txt'.unicode_normalize(:nfc)
puts file.encode('cp1252')
(It appears that Stack Overflow is normalizing the string when displaying your question, which is probably why copying the code from the question and running it doesn’t produce any errors.)
This will avoid the error, but note that it is not necessarily possible to reverse the process to get the original string unless the original is in a known normalized form already.
I'm having a character encoding issue with a Ruby script that does some HTML scraping and parsing with the Nokogiri gem. At one point in the script, I call join("\n") on an array of strings that have been pulled from some HTML, which causes this error:
./script.rb:333:in `join': incompatible character encodings: UTF-8 and ASCII-8BIT (Encoding::CompatibilityError)
In my logs, I can see Café showing up for some of the strings that would be included in the join operation.
Is it that some of the strings in my array to be joined are ASCII-8BIT and some are UTF-8 and ruby can't combine them? Do I need to convert or sanitize my strings after parsing them with Nokogiri (into UTF-8)?.
I tried force_encoding('UTF-8') and encode('UTF-8') on the scraped HTML content before I do anything else with it, but it didn't help. In fact, after I tried encode('UTF-8'), my script crashed even earlier when it called to_s on a string containing Café.
Character encoding always really confuses me. Is there something else I can do to sanitize the strings to avoid this error?
Edit:
I was doing something similar in Perl recently and used a module called Text::Unidecode and was able to pass my strings to a function that translates any problematic characters e.g. the letter a with an acute to the plain letter a. Is there anything similar for ruby? (This isn't necessarily what I'm aiming for though, if I can keep the a with acute then that's preferable I think.
Edit2:
I'm really confused by this and it's proving difficult to reproduce reliably. Here's some code:
[CODE REMOVED]
Edit3:
I removed the previously posted code example because it wasn't correct. But the bottom line is, whenever I try to print or call to_s on the string that was scraped, I get the encoding error.
Edit4:
It turned out in the end that the scraped html input was not what was causing the problem. I got the encoding error whenever I tried to print or call to_s on a hash containing, among other things, the scraped html text. The 'other things' were values from database queries, and they were being returned in ASCII-8BIT. To fix the issue, I explicitly had to call force_encoding('UTF-8') on each database value that I use (although I hear that the mysql2 gem does this automatically so I should switch to that).
I hate character encoding.
Presumably, Café is supposed to be Café. If we start out with Café in UTF-8 but treat the bytes as though they were encoded in ISO-8859-1 (AKA Latin-1) and then re-encode them as UTF-8, we get the Café that you're seeing; for example:
> s = 'Café'
=> "Café"
> s.encoding
=> #<Encoding:UTF-8>
> s.force_encoding('iso-8859-1').encode('utf-8')
=> "Café"
So somewhere you're reading a UTF-8 string but treating it as Latin-1 and re-encoding it as UTF-8. I'd guess that Nokogiri is reading the page and thinking that it is Latin-1 or being told by your user agent that it is getting Latin-1 text. Perhaps you have a bad default encoding somewhere, or the HTTP headers are lying about the encoding, or the page itself is lying about its encoding.
You need to get everything into UTF-8 at the edges of your scraper. Figure out who is lying about the encoding and sort it out right there.
Don't feel bad, scraping and encoding is a nightmare of confusion, stupidity, guesswork, and hard liquor. Servers lie, pages lie, browsers lie, no one is happy.
I have the following string:
l\u0092issue
My question is how to convert it to utf8 characters ?
I have tried that
1.9.3p484 :024 > "l\u0092issue".encode('utf-8')
=> "l\u0092issue"
You seem to have got your encodings into a bit of a mix up. If you haven’t already, you should first read Joel Spolsky’s article The Absolute Minimum Every Software Developer Absolutely, Positively Must Know About Unicode and Character Sets (No Excuses!) which provides a good introduction into this type of thing. There is a good set of articles on how Ruby handles character encodings at http://graysoftinc.com/character-encodings/understanding-m17n-multilingualization. You could also have a look at the Ruby docs for String and Encoding.
In this specific case, the string l\u0092issue means that the second character is the character with the unicode codepoint 0x92. This codepoint is PRIVATE USE TWO (see the chart), which basically means this position isn’t used.
However, looking at the Windows CP-1252 encoding, position 0x92 is occupied by the character ’, so if this is the missing character the the string would be l’issue, whick looks a lot more likely even though I don’t speak French.
What I suspect has happened is your program has received the string l’issue encoded in CP-1252, but has assumed it was encoded in ISO-8859-1 (ISO-8859-1 and CP-1252 are quite closely related) and re-encoded it to UTF-8 leaving you with the string you now have.
The real fix for you is to be careful about the encodings of any strings that enter (and leave) your program, and how you manage them.
To transform your string to l’issue, you can encode it back to ISO-8859-1, then use force_encoding to tell Ruby the real encoding of CP-1252, and then you can re-encode to UTF-8:
2.1.0 :001 > s = "l\u0092issue"
=> "l\u0092issue"
2.1.0 :002 > s = s.encode('iso-8859-1')
=> "l\x92issue"
2.1.0 :003 > s.force_encoding('cp1252')
=> "l\x92issue"
2.1.0 :004 > s.encode('utf-8')
=> "l’issue"
This is only really a demonstration of what is going on though. The real solution is to make sure you’re handling encodings correctly.
That is encoded as UTF-8 (unless you changed the original string encoding). Ruby is just showing you the escape sequences when you inspect the string (which is why IRB does there). \u0092 is the escape sequence for this character.
Try puts "l\u0092issue" to see the rendered character, if your terminal font supports it.
I'm reading "The Ruby Programming Language". In section 3.2.6.1, "Multibyte characters in Ruby 1.9", the book introduces an optimization in Ruby's string
If a string literal contains only 7-bit ASCII characters, then its encoding method will return ASCII, even if the source encoding is UTF-8
I tried the following simple script on both ruby 1.9.1-p431, 1.9.2 and 1.9.3-p125, both uses UTF-8 encoding for 7-bit ASCII characters.
# coding: utf-8
s = 'hello'
p s.encoding
# result is #<Encoding:UTF-8>
I guess maybe this behavior is changed during the development of Ruby 1.9. I tried to search Ruby 1.9's changelog, and the 1.9.1 changelog confirms this behavior. I also cloned Ruby's git repository but I can't find the commit mentioning about changing this behavior.
Update:
Looking at Ruby's source code repository, I guess this is the behavior in Ruby 1.9.0, which was released in Jan, 2008. (It failed to compile on Debian 6 so I can't exactly confirm this.) Though "The Ruby Programming Language" is an excellent book, it's originally published in 2008. It's very likely that some descriptions in the book are outdated.
Another outdated description is about the Encoding.list method behavior. So be careful of outdated description if you are also reading this book.
I don't have that book, but The current Pdf version of the Programming Ruby book (the pickaxe) states
String literals are always encoded using the encoding of the source file that contains them, regardless of the content of the string
And then gives an example where "dog" gains the utf-8 encoding. Looks like the edition of the book you have is wrong. Whether that was an errata in the print version of your book or just the fact that ruby changed after it was printed, I don't know
It's important to note that "encoding" in Ruby often refers to "interpretation" more than the actual bytes stored. When it says the encoding is UTF-8, that means that the bytes in that string will be interpreted as UTF-8 multi-byte characters, though given that UTF-8 is backwards-compatible with 7-bit ASCII by design, there is no obvious difference on the binary level.
Ruby does not automatically detect the encoding of your strings as there isn't a standard or even reliable method for determining this. This is why the default encoding method is applied to all strings unless explicitly specified when created or converted.
You can switch the encoding of the string without actually modifying the stored bytes using force_encoding. You can also convert to a different format, potentially re-mapping the stored bytes, using encode.
If you want to know more about the internals of a string you have several methods to explore:
'dog'.encoding
# => #<Encoding:UTF-8>
'dog'.bytes.to_a
# => [100, 111, 103]
'dog'.chars.to_a
# => ["d", "o", "g"]
Compare with a non 7-bit ASCII string:
'døg'.encoding
# => #<Encoding:UTF-8>
'døg'.bytes.to_a
# => [100, 195, 184, 103]
'døg'.chars.to_a
# => ["d", "ø", "g"]