Change url in a string if present

Question

Sorry I am new to regex so please forgive me . I have several strings such as

"mso-table-lspace:0;mso-table-rspace:0;margin:0;padding:0;background: url(http://someurl/lib/id/w/download_bg.jpg) no-repeat top left #f9f9f9; text-align:center;"

"font-size: 3px; line-height: 3px;"

I want to first check if string contains a image url ( which contains https? and .png or .jpeg or .jpg) and if present in string replace it with a different url.

So for first string the output should be

"mso-table-lspace:0;mso-table-rspace:0;margin:0;padding:0;background: url(http://someotherurl/lib/id/w/download_bg.jpg) no-repeat top left #f9f9f9; text-align:center;"

Avinash Raj · Accepted Answer · 2014-09-02 10:40:41Z

1

You could try the below gsub command,

gsub(/^(.*?https?:\/\/)([^\/]*)(.*?(?:\.png|\.jpeg|\.jpg))/, '\1someotherurl\3')

Code:

> IO.write("/path/to/the/file", File.open("/path/to/the/file") {|f| f.read.gsub(/^(.*?https?:\/\/)([^\/]*)(.*?(?:\.png|\.jpeg|\.jpg))/, '\1someotherurl\3')})
=> 201

Example:

irb(main):006:0> "mso-table-lspace:0;mso-table-rspace:0;margin:0;padding:0;background: url(http://someurl/lib/id/w/download_bg.jpg) no-repeat top left #f9f9f9; text-align:center;".gsub(/^(.*?https?:\/\/)([^\/]*)(.*?(?:\.png|\.jpeg|\.jpg))/, '\1someotherurl\3')
=> "mso-table-lspace:0;mso-table-rspace:0;margin:0;padding:0;background: url(http://someotherurl/lib/id/w/download_bg.jpg) no-repeat top left #f9f9f9; text-align:center;"

edited Sep 2, 2014 at 10:40

answered Sep 2, 2014 at 10:29

Avinash Raj

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Uri Agassi · Accepted Answer · 2014-09-02 11:23:21Z

1

Since your input is CSS, I think it would be pretty safe to assume you are looking for something of this form

url(<http or https>://<some url>/<some path>.<image extension>)

for this, a simplified regex (not needing the complicated regex for actually trying to match URL, and might be very non-trivial) could be used:

text.gsub(%r{(url\(https?://)[^/]+/([^\)]+\.(png|jpeg|jpg))\)}, '\1someotherurl/\2')
# => "mso-table-lspace:0;mso-table-rspace:0;margin:0;padding:0;
#     background: url(http://someotherurl/lib/id/w/download_bg.jpg no-repeat 
#     top left #f9f9f9; text-align:center;"

answered Sep 2, 2014 at 11:23

Uri Agassi

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vks · Accepted Answer · 2014-09-02 10:49:17Z

0

(?=.*?(?:http|https):\/\/.*\/.*?\.(?:jpg|png|jpeg).*)(.*?)https?:\/\/.*\/.*?\)(.*)

Try this.This works for all the cases.

See demo.

http://regex101.com/r/kJ6rS7/1

answered Sep 2, 2014 at 10:49

vks

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shivam · Accepted Answer · 2014-09-02 10:30:21Z

-1

It can be done in many ways, one simple example

a = "mso-table-lspace:0;mso-table-rspace:0;margin:0;padding:0;background: url(http://someurl/lib/id/w/download_bg.jpg) no-repeat top left #f9f9f9; text-align:center;"

Now,

a.gsub(a.scan(/http(.*?)(jpg|png)/)[0][0],"://someother-url") if  a.scan(/http(.*?)(jpg|png)/).size > 0
# => "mso-table-lspace:0;mso-table-rspace:0;margin:0;padding:0;background: url(http://someother-urljpg) no-repeat top left #f9f9f9; text-align:center;"

answered Sep 2, 2014 at 10:30

shivam

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1 Comment

Uri Agassi Over a year ago

This solution is very buggy - it assumes there is only one match, and then it uses gsub on the match itself, assuming it is not used anywhere else (consider text "http://abc/this.jpg not_a_url_://abc/this.should.not.be.replaced"). It also scans the string twice, which is not very efficient...

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