Match Pattern and write following value as variable

Question

I'm trying to match a pattern and then pull the following information to create a file using that variable.

Example (my data may look like either of the 2 examples)

"headers": {
            "content-type": "application/octet-stream;\r\n\tname=\"I may have long file names - With lots of spaces.zip\"",
            "content-transfer-encoding": "base64",
            "content-disposition": "attachment;\r\n\tfilename=\"I may have long file names - With lots of spaces.zip\""

or

"headers": {
            "content-type": "application/octet-stream",
            "content-transfer-encoding": "base64",
            "content-disposition": "attachment; filename=tiny.exe"

Basically I'm trying to create a new file named as the filename. So example 1 has a really long filename with spaces and hypens, example 2 has a short filename. Example 1 is identified by 'tfilename' and example 2 'filename' .

Obviously I don't need the double quotes.

Can anyone assist with this please?

Thanks!

Answer 1

I would consider using a language that can parse the JSON and manipulate the data. Here's some ruby (and shell)

$ cat data.json 
{
    "headers": {
        "content-type": "application/octet-stream;\r\n\tname=\"I may have long file names - With lots of spaces.zip\"",
        "content-transfer-encoding": "base64",
        "content-disposition": "attachment;\r\n\tfilename=\"I may have long file names - With lots of spaces.zip\""
    }
}

$ filename=$(ruby -rjson -e '
    data = JSON.parse(File.read(ARGV.shift))
    m = data["headers"]["content-disposition"].match(/filename=(.+)$/m)
    filename = m[1].gsub(/^"|"$/,"")
    puts filename
' data.json)

$ echo "$filename"
I may have long file names - With lots of spaces.zip