I need to read a file from the file system and load the entire contents into a string in a groovy controller, what's the easiest way to do that?
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6 Answers
String fileContents = new File('/path/to/file').text If you need to specify the character encoding, use the following instead:
String fileContents = new File('/path/to/file').getText('UTF-8') 
5 Comments
das Keks
Do I have to execute some close() statements or will the reader be closed by the getText() method?
Dónal
@dasKeks I think it's safe to assume that the implementation of this method closes any necessary resources. Anyway, you don't have access to any reader that may be created, so you can't close it
ArtOfWarfare
I'd like to mention that this works even if the
File object originated from an ordinary java jar. I wasn't sure if maybe Groovy had its own special File class with the text attribute, or something, but it seems that it doesn't matter where the File object comes from, whether it's instantiated by Groovy code or Java code.
roens
FWIW, I found that unless I dropped
String from the beginning of that line, the variable ended up empty.
Jeff Scott Brown
@roens That makes no sense. I suspect there is some other factor in the mix like you had a local variable that was hiding a field or something like that.
The shortest way is indeed just
String fileContents = new File('/path/to/file').text but in this case you have no control on how the bytes in the file are interpreted as characters. AFAIK groovy tries to guess the encoding here by looking at the file content.
If you want a specific character encoding you can specify a charset name with
String fileContents = new File('/path/to/file').getText('UTF-8') See API docs on File.getText(String) for further reference.
2 Comments
Ian Roberts
+1 for recommending the version that takes an encoding parameter. The plain
someFile.text doesn't make an intelligent guess, it simply uses the platform default encoding (usually UTF-8 on modern Linuxes, but something like windows-1252 or MacRoman on Windows/Mac OS, unless you've overridden it with -Dfile.encoding=...)
Matthijs Bierman
In recent versions of Groovy at least, the guess is done using CharsetToolkit which does make an intelligent guess.
A slight variation...
new File('/path/to/file').eachLine { line -> println line } 
2 Comments
Steve Byrne
True, but it's still a useful idiom to capture "for the record".
Bill K
It's a good thing to see this--makes processing a file line by line trivial.
In my case new File() doesn't work, it causes a FileNotFoundException when run in a Jenkins pipeline job. The following code solved this, and is even easier in my opinion:
def fileContents = readFile "path/to/file" I still don't understand this difference completely, but maybe it'll help anyone else with the same trouble. Possibly the exception was caused because new File() creates a file on the system which executes the groovy code, which was a different system than the one that contains the file I wanted to read.
4 Comments
sirineBEJI
Does readFile step works fine for you? for me it works but it makes ' ' single quotes on some words, I don't understand !
P Kuijpers
It works fine for me, and didn't encounter any quotes I didn't place myself (I guess you mean quotes in the file contents). Maybe worth to create a new question for this? In that case, try to specify in which cases the quotes appear and where exactly.
ashish
Works for jenkins. as readFile is an internal keyword, and does not need any import or extra approval from jenkins-admin. The whole file can be read in String var and then printed via below code:
String fp_f = readFile("any_file") if (fp.length()) { currentBuild.description = fp } Also, if file is not found then there is error.
Cyborg-X1
Btw. the reason for this is, that new File() looks for files on your computer, as readFile in Jenkins looks in the groovy sandbox of the java vm where your pipeline stuff is probably running ... Also you are allowed to use readfile in sandboxed pipelines but using File() is by default not allowed, File you will have to whitelist in Jenkins settings before you can use it.
the easiest way would be
which means you could just do:
new File(filename).text 
Comments
Here you can find some other way to do the same.
Read file.
File file1 = new File("C:\Build\myfolder\myTestfile.txt"); def String yourData = file1.readLines(); Read full file.
File file1 = new File("C:\Build\myfolder\myfile.txt"); def String yourData= file1.getText(); Read file line-bye-line.
File file1 = new File("C:\Build\myfolder\myTestfile.txt"); for (def i=0;i<=30;i++) // specify how many line need to read eg.. 30 { log.info file1.readLines().get(i) } Create a new file.
new File("C:\Temp\FileName.txt").createNewFile(); 
3 Comments
Manuel Perez Heredia
I am not sure you need
def when you specify the type.
shashi singh
Without using def code will work, I have a habit to define those variable!
Alexander Samoylov
I like readLines() approach, because it works as in a normal (console) groovy as in the Jenkins Pipeline.