将字符串解析为命令行的数组输出

Question

I'm working on a new Symfony 2 project which will be a panel management for Docker containers.

In this project, I'm executing some commands with the exec() PHP function.

I'm trying to parse the output of the following command :

docker create tutum/lamp:latest --name test 2>&1

When the command is a success I'm getting the container ID in a string which is good and easy to use but when a problem occured it's not the same. The result is a string with a var="data" syntax which I want to parse in order to get an array.

The command output :

time="2015-06-21T11:33:26+02:00" level="fatal" msg="Error response from daemon: Conflict. The name \"test\" is already in use by container XXXXXXXX. You have to delete (or rename) that container to be able to reuse that name."

I wish to have something like that :

Array( time => "2015-06-21T11:33:26+02:00", level => "fatal" ...);

I know that I have to do a regex parsing. After a while (regex and me are not realy best friends) I get this regex (tested on https://regex101.com/) :

/([a-zA-Z]+)="((.*)*)"/

I used preg_split function i'm not sure that it's the good one.

preg_split('/([a-zA-Z]+)="((.*)*)"/', $output)

Result is :

array(2) { [0]=> string(0) "" [1]=> string(0) "" }

Have you any suggestions to help me ? Many thanks for your help.

Answer 1

TL;DR: This should work:

preg_match_all(',([a-z]+)="((?:[^"]|\\\\")*[^\\\\])",', $a, $matches, PREG_SET_ORDER);
var_dump($matches);

The last var_dump prints the following data structure, which should be easy to process:

array(3) {
  [0] => array(3) {
    [0] => string(32) "time="2015-06-21T11:33:26+02:00""
    [1] => string(4) "time"
    [2] => string(25) "2015-06-21T11:33:26+02:00"
  }
  [1] => array(3) {
    [0] => string(13) "level="fatal""
    [1] => string(5) "level"
    [2] => string(5) "fatal"
  }
  [2] => array(3) {
    [0] => string(179) "msg="Error response from daemon: Conflict. The name \\"test\\" is already in use by container XXXXXXXX. You have to delete (or rename) that container to be able to reuse that name.""
    [1] => string(3) "msg"
    [2] => string(173) "Error response from daemon: Conflict. The name \\"test\\" is already in use by container XXXXXXXX. You have to delete (or rename) that container to be able to reuse that name."
  }
}

Why this works

The regular expression explained:

([a-z]+)                    # Match the label ("time", "level" or "msg")
=                           # Self-explanatory
"((?:[^"]|\\\\")*[^\\\\])"  # This is the tricky part:
                            # Match the quoted string; this is a sequence
                            # of (a) non-quote characters ([^"]) or
                            # (b) escaped quote characters (\\\\").

Some other notes:

1. preg_split uses the regular expression to match token at which the string should be split. That's not what you want in this case; you want to return the parts of the string that was matched by the regular expression. For this, you should use preg_match (or if, like here, you want a pattern to match multiple times), preg_match_all.
2. Also consider the PREG_SET_ORDER flag for preg_match_all. This flag causes the $matches result to contain one row for each label from output message, which makes the data structure easy to process. Try and see what happens if you leave it out.