# Trouble reading a gzipped xml-file **URL:** \ **Category:** Ruby\ **Created:** [November 14, 2005, 4:05pm UTC](https://www.ruby-forum.com/t/trouble-reading-a-gzipped-xml-file/47848 "2005-11-14T16:05:06Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![guido.de-melo](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/a9adbd/32.png) [@guido.de-melo](https://www.ruby-forum.com/u/guido.de-melo)\ **Post date:** [November 14, 2005, 4:05pm UTC](https://www.ruby-forum.com/t/trouble-reading-a-gzipped-xml-file/47848/1 "2005-11-14T16:05:06Z")
Hi, I’m trying to read a gzipped xml-file into rexml, but I don’t quite succeed. Perhaps someone can help me. Till now I tried this: #!/usr/bin/ruby -w require ‘zlib’ require ‘rexml/document’ Zlib::GzipReader.open(‘file.dia’) {|gz| print gz.read } # this prints everything nicely and it works f = Zlib::GzipReader.open(“file.dia”) s = f.read p s # now the ungzipped contents are in s, they look like this however: # "\\n\\n # dia:diagramdata\n \\n # all in one line and encapsulated in “” # so of course the next command fails xmldoc = REXML::Document.new s p xmldoc # gives: … \ Any ideas on this? This can’t be too difficult, I think… Guido ---
**Author:** ![guido.de-melo](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/a9adbd/32.png) [@guido.de-melo](https://www.ruby-forum.com/u/guido.de-melo)\ **Post date:** [November 14, 2005, 4:20pm UTC](https://www.ruby-forum.com/t/trouble-reading-a-gzipped-xml-file/47848/2 "2005-11-14T16:20:08Z")
Guido de Melo wrote: > Zlib::GzipReader.open(‘file.dia’) {|gz| > print gz.read > } > > # this prints everything nicely and it works > > f = Zlib::GzipReader.open(“file.dia”) > s = f.read > p s You’re not closing f here. > # now the ungzipped contents are in s, they look like this however: > > # "\\n\ > # xmlns:dia="[http://www.lysator.liu.se/~alla/dia/\](http://www.lysator.liu.se/~alla/dia/%5C)"\>\n > > # dia:diagramdata\n \\n > > # all in one line and encapsulated in “” > > # so of course the next command fails I’m not so sure that it fails just because of this. > xmldoc = REXML::Document.new s > p xmldoc > > # gives: … \ > > Any ideas on this? This can’t be too difficult, I think… > Guido Did you try this? xmldoc = Zlib::GzipReader.open(‘file.dia’) {|gz| REXML::Document.new gz} Kind regards ``` robert ``` ---
**Author:** ![guido.de-melo](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/a9adbd/32.png) [@guido.de-melo](https://www.ruby-forum.com/u/guido.de-melo)\ **Post date:** [November 14, 2005, 4:29pm UTC](https://www.ruby-forum.com/t/trouble-reading-a-gzipped-xml-file/47848/3 "2005-11-14T16:29:09Z")
Robert K. wrote: > You’re not closing f here. […] > I’m not so sure that it fails just because of this. It shouldn’t, because ruby will determine the end of the file by itself and close the handle on exiting. > Did you try this? > > xmldoc = Zlib::GzipReader.open(‘file.dia’) {|gz| REXML::Document.new gz} irb(main):003:0\> xmldoc = Zlib::GzipReader.open(‘file.dia’) {|gz| REXML::Document.new gz} RuntimeError: Zlib::GzipReader is not a valid input stream. It must be either a String, IO, StringIO or Source. This doesn’t work either, I’m afraid… Guido ---
**Author:** ![guido.de-melo](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/a9adbd/32.png) [@guido.de-melo](https://www.ruby-forum.com/u/guido.de-melo)\ **Post date:** [November 14, 2005, 4:44pm UTC](https://www.ruby-forum.com/t/trouble-reading-a-gzipped-xml-file/47848/4 "2005-11-14T16:44:12Z")
Guido de Melo wrote: > Robert K. wrote: > > > You’re not closing f here. > > […] > > > I’m not so sure that it fails just because of this. > > It shouldn’t, because ruby will determine the end of the file by > itself and close the handle on exiting. I didn’t mean to say that it fails because of the open file. My point with the first remark was that it’s a good habit to open files for only as long as they are actually used. The block form is the idiom of choice here: it’s not much longer as a simple File.open() or File.new() and it ensures the file is always properly closed. > This doesn’t work either, I’m afraid… > I guess this is because GzipReader doesn’t inherit IO: > > Zlib::GzipReader.ancestors > > =\> [Zlib::GzipReader, Enumerable, Zlib::GzipFile, Object, Kernel] But you can do this xmldoc = Zlib::GzipReader.open(‘file.dia’) {|gz| REXML::Document.new( gz.read )} Btw, you see differing output because you use different printing methods: Zlib::GzipReader.open(‘file.dia’) {|gz| print gz.read } vs. p s If there is no exception during GZIP reading I guess there might be a bug somewhere. As a test I’d write the gunzipped content to another file and do a diff on the plain xml and this output to see whether GzipReader actually yields the same content. Btw, did you actually try to make REXML read the first variant? Maybe you have a problem in your XML file. Kind regards ``` robert ``` ---
**Author:** ![guido.de-melo](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/a9adbd/32.png) [@guido.de-melo](https://www.ruby-forum.com/u/guido.de-melo)\ **Post date:** [November 14, 2005, 5:08pm UTC](https://www.ruby-forum.com/t/trouble-reading-a-gzipped-xml-file/47848/5 "2005-11-14T17:08:16Z")
Thank you very much! You solved it! Robert K. wrote: > here: it’s not much longer as a simple File.open() or File.new() and it > ensures the file is always properly closed. You are right of course, I will try to do this in the future. > But you can do this > > xmldoc = Zlib::GzipReader.open(‘file.dia’) {|gz| REXML::Document.new( > gz.read )} And this worked perfect for me 🙂 > If there is no exception during GZIP reading I guess there might be a bug > somewhere. As a test I’d write the gunzipped content to another file and > do a diff on the plain xml and this output to see whether GzipReader > actually yields the same content. They do > Btw, did you actually try to make REXML read the first variant? Maybe you > have a problem in your XML file. Thank goodness the XML produced by dia is sound 🙂 Kind regards, Guido