Código de Python - Clase para editar un archivo de configuración

#!/usr/bin/env python

# -*- coding: utf-8 -*-

"""

Class for read and modify files with key value content.

Last versión:

http://lwp-l.com/s5436

Samples:

    Read key for file with separation is "="

        sample fileConfig content:

            # comment

            key1=value1

        code:

            from keyValueFile import KeyValueFile

            kv=KeyValueFile("fileConfig", "=")

            kv.getValue("key1") # return value1

    Read key commented for file with separation is "=" and comment line started with "#"

        sample fileConfig content:

            # comment

            key1=value1

            #key2=value2

        code:

            from keyValueFile import KeyValueFile

            kv=KeyValueFile("fileConfig", "=")

            kv.getValue("key2", True) # return value2

    Read key commented for file with separation is "=" and comment line started with ";"

        sample fileConfig content:

            ; comment

            key1=value1

            ;key2=value2

        code:

            from keyValueFile import KeyValueFile

            kv=KeyValueFile("fileConfig", "=", ";")

            kv.getValue("key2", True) # return value2

    Read key for file with separation is one space " "

        sample fileConfig content:

            # comment

            key2 value2

        code:

            from keyValueFile import KeyValueFile

            kv=KeyValueFile("fileConfig", " ")

            kv.getValue("key2") # return value2

    Update value for file with separation is "="

        sample fileConfig content:

            # comment

            key1=value1

        code:

            from keyValueFile import KeyValueFile

            kv=KeyValueFile("fileConfig", "=")

            kv.setValue("key1", "new value")

            kv.save()

    Get commented value for a file with separation is "=" and comment line started with ";"

        sample fileConfig content:

            ; comment

            key1=value1

            ;key2=value2

        code:

            from keyValueFile import KeyValueFile

            kv=KeyValueFile("fileConfig", "=", ";")

            kv.getValue("key2") # return None

            kv.getValue("key2", True) # return value2

    Set commented for a key value pairs

        sample fileConfig content:

            ; comment

            key1=value1

            key2=value2

        code:

            from keyValueFile import KeyValueFile

            kv=KeyValueFile("fileConfig", "=", ";")

            kv.setValue("key2", kv.getValue("key2"), True)

            kv.save()

    Remove commented for a key value pairs

        sample fileConfig content:

            ; comment

            key1=value1

            ;key2=value2

        code:

            from keyValueFile import KeyValueFile

            kv=KeyValueFile("fileConfig", "=", ";")

            kv.setValue("key2", kv.getValue("key2", True))

            kv.save()

    Remove key value pairs from file

        sample fileConfig content:

            # comment

            key1=value1

            key2=value2

        code:

            from keyValueFile import KeyValueFile

            kv=KeyValueFile("fileConfig")

            kv.removeKey("key2") # remove the line key2=value2

            kv.save()

"""

import os

from tempfile import mkstemp

from shutil import move

__ver__="0.1"

class KeyValueFile():

    file=""

    separationKeyValue=""

    commentCharacterStart=""

    keyValues={}

    keyRemove=[]

    def __init__(self, file="", separationKeyValue="=", commentCharacterStart="#"):

        """

        Parameters:

            file string - file to read and save

            separation string - separation between key and value

        """

        self.setFile(file)

        self.separationKeyValue=separationKeyValue

        self.commentCharacterStart=commentCharacterStart

    def setFile(self, file, separationKeyValue="="):

        """

        Function that receive a filename to update.

        Parameters

            string file

            string separationKeyValue (default =)

        Return

            boolean

        """

        if os.path.exists(file) and separationKeyValue:

            self.file=file

            self.separationKeyValue=separationKeyValue

            return True

        return False

    def setValue(self, key, value="", comment=False):

        """

        Function to save key value in a var for update or insert when save data.

        Parameters:

            string key

            string value (optional)

            boolean comment - define if the value has to be commented

        Return:

            boolean

        """

        if not key:

            return False

        if key in self.keyRemove:

            self.keyRemove.remove(key)

        self.keyValues[key.strip()]=[value.strip(), comment]

        return True

    def removeKey(self, key):

        """

        Function to save key value for remove this line with key when save data.

        Parameters:

            string key

        """

        if not key:

            return False

        if key in self.keyValues:

            del self.keyValues[key]

        self.keyRemove.append(key)

        return True

    def getValue(self, key, commented=False):

        """

        Function that find a key into file and return a value if finded key.

        Parameters:

            key string 

            commented boolean - define if search key in commented lines

        Return:

            string - value for a key or None

        """

        with open(self.file, "r") as f:

            for line in f:

                kv=line.split(self.separationKeyValue, 1)

                # the line doesn't have a separation key value

                if len(kv)==1:

                    continue

                k,v=kv

                k=k.strip()

                v=v.strip()

                k=k[1:].strip() if commented and k[0]==self.commentCharacterStart else k

                if k==key:

                    return v

        return None

    def save(self):

        """

        Function to save the content of vars in a file.

        Return:

            int - number of lines + added or updated - removed

        """

        count=0

        if os.path.exists(self.file) and os.access(self.file, os.W_OK) and self.separationKeyValue:

            fh, abs_path = mkstemp()

            with os.fdopen(fh, 'w') as new_file:

                with open(self.file, "r") as old_file:

                    for line in old_file:

                        kv=line.split(self.separationKeyValue, 1)

                        if len(kv)==1:

                            # the line doesn't have a separation key value

                            new_file.write(line)

                            continue

                        k,v=kv

                        k=k.strip()

                        v=v.strip()

                        k=k[1:] if k[0]==self.commentCharacterStart else k

                        if k and k in self.keyRemove:

                            # this key if market as remove

                            count-=1

                            self.keyRemove.remove(k)

                            continue

                        if k and k in self.keyValues:

                            # this key will update from file

                            count+=1

                            if self.keyValues[k][1]==True:

                                # write as commented

                                new_file.write(self.commentCharacterStart+k+self.separationKeyValue+self.keyValues[k][0]+"\n")

                            else:

                                new_file.write(k+self.separationKeyValue+self.keyValues[k][0]+"\n")

                            del self.keyValues[k]

                        else:

                            new_file.write(line)

                    # Add elements not updated

                    for k,v in self.keyValues.items():

                        count+=1

                        new_file.write(k+self.separationKeyValue+v[0]+"\n")

                    self.keyValues={}

                    self.keyRemove=[]

            # Remove original file

            os.remove(self.file)

            # Move new file

            move(abs_path, self.file)

        return count