Pandas, Numpy, Encryption/Decryption, Hidden Files In Python (Crossover between Space Stone, Reality Stone & Mind Stone of Python-Verse)

So, here we come up with another crossover of Space Stone, Reality Stone & Mind Stone of Python-Verse. It is indeed exciting & I cannot wait to explore that part further. Today, in this post, we’ll see how one application can integrate all these key ingredients in Python to serve the purpose. Our key focus will be involving popular packages like Pandas, Numpy & Popular Encryption-Decryption techniques, which include some hidden files as well.

So, our objective here is to proceed with the encryption & decryption technique. But, there is a catch. We need to store some salt or tokenized value inside a hidden file. Our application will extract the salt value from it & then based on that it will perform Encrypt/Decrypt on the data.

Why do we need this approach?

The answer is simple. On many occasions, we don’t want to store our right credentials in configuration files. Also, we don’t want to keep our keys to open to other developers. There are many ways you can achieve this kind of security.  Today, I’ll be showing a different approach to make the same.

Let’s explore.

As usual, I’ll provide the solution, which is tested in Windows & MAC & provide the script. Also, I’ll explain the critical lines of those scripts to understand it from a layman point of view. And, I won’t explain any script, which I’ve already explained in my earlier post. So, you have to refer my old post for that.

To encrypt & decrypt, we need the following files, which contains credentials in a csv. Please find the sample data –

Config_orig.csv

Orig_File

Please see the file, which will be hidden by the application process.

Token_Salt_File

As you can see, this column contains the salt, which will be used in our Encryption/Decryption.

1. clsL.py (This script will create the csv files or any intermediate debug csv file after the corresponding process. Hence, the name comes into the picture.)

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###########################################
#### Written By: SATYAKI DE        ########
#### Written On: 25-Jan-2019       ########
####                               ########
#### Objective: Log File           ########
###########################################
import pandas as p
import platform as pl
from clsParam import clsParam as cf

class clsL(object):
    def __init__(self):
        self.path = cf.config['PATH']

    def logr(self, Filename, Ind, df, subdir=None):
        try:
            x = p.DataFrame()
            x = df
            sd = subdir

            os_det = pl.system()

            if sd == None:
                if os_det == "Windows":
                    fullFileName = self.path + '\\' + Filename
                else:
                    fullFileName = self.path + '/' + Filename
            else:
                if os_det == "Windows":
                    fullFileName = self.path + '\\' + sd + "\\" + Filename
                else:
                    fullFileName = self.path + '/' + sd + "/" + Filename

            if Ind == 'Y':
                x.to_csv(fullFileName, index=False)

            return 0

        except Exception as e:
            y = str(e)
            print(y)
            return 3

2. clsParam.py (This is the script that will be used as a parameter file & will be used in other python scripts.)

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###########################################
#### Written By: SATYAKI DE        ########
#### Written On: 25-Jan-2019       ########
#### Objective: Parameter File     ########
###########################################

import os
import platform as pl

class clsParam(object):

    config = {
        'FILENAME' : 'test.amca',
        'OSX_MOD_FILE_NM': '.test.amca',
        'CURR_PATH': os.path.dirname(os.path.realpath(__file__)),
        'NORMAL_FLAG': 32,
        'HIDDEN_FLAG': 34,
        'OS_DET': pl.system()
    }

 

3. clsWinHide.py (This script contains the core logic of hiding/unhiding a file under Windows OS. Hence, the name comes into the picture.)

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###########################################
#### Written By: SATYAKI DE          ######
#### Written On: 25-Jan-2019         ######
####                                 ######
#### This script will hide or Unhide ######
#### Files in Windows.               ######
###########################################

import win32file
import win32con
from clsParam import clsParam as cp

class clsWinHide(object):
    def __init__(self):
        self.path = cp.config['CURR_PATH']
        self.FileName = cp.config['FILENAME']
        self.normal_file_flag = cp.config['NORMAL_FLAG']

    def doit(self):
        try:
            path = self.path
            FileName = self.FileName

            FileNameWithPath = path + '\\' + FileName
            flags = win32file.GetFileAttributesW(FileNameWithPath)
            win32file.SetFileAttributes(FileNameWithPath,win32con.FILE_ATTRIBUTE_HIDDEN | flags)

            return 0
        except Exception as e:
            x = str(e)
            print(x)

            return 1

    def undoit(self):
        try:
            path = self.path
            FileName = self.FileName
            normal_file_flag = self.normal_file_flag

            FileNameWithPath = path + '\\' + FileName
            win32file.SetFileAttributes(FileNameWithPath,win32con.FILE_ATTRIBUTE_NORMAL | int(normal_file_flag))

            return 0
        except Exception as e:
            x = str(e)
            print(x)

            return 1

Key lines that we would like to explore are as follows –

def doit()

flags = win32file.GetFileAttributesW(FileNameWithPath)
win32file.SetFileAttributes(FileNameWithPath,win32con.FILE_ATTRIBUTE_HIDDEN | flags)

The above two lines under doit() functions are changing the file attributes in Windows OS to the hidden mode by assigning the FILE_ATTRIBUTE_HIDDEN property.

def undoit()

normal_file_flag = self.normal_file_flag

FileNameWithPath = path + '\\' + FileName
win32file.SetFileAttributes(FileNameWithPath,win32con.FILE_ATTRIBUTE_NORMAL | int(normal_file_flag))

As the script suggested, the application is setting the file attribute of a hidden file to FILE_ATTRIBUTE_NORMAL & set the correct flag from parameters, which leads to the file appears as a normal windows file.

4. clsOSXHide.py (This script contains the core logic of hiding/unhiding a file under OSX, i.e., MAC OS. Hence, the name comes into the picture.)

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###########################################
#### Written By: SATYAKI DE           #####
#### Written On: 25-Jan-2019          #####
####                                  #####
#### Objective: This script will hide #####
#### or Unhide the file in OSX.       #####
###########################################

import os
from clsParam import clsParam as cp

class clsOSXHide(object):
    def __init__(self):
        self.path = cp.config['CURR_PATH']
        self.FileName = cp.config['FILENAME']
        self.OSX_Mod_FileName = cp.config['OSX_MOD_FILE_NM']
        self.normal_file_flag = cp.config['NORMAL_FLAG']

    def doit(self):
        try:
            path = self.path
            FileName = self.FileName

            FileNameWithPath = path + '/' + FileName
            os.rename(FileNameWithPath, os.path.join(os.path.dirname(FileNameWithPath),'.'
                                                     + os.path.basename(FileNameWithPath)))

            return 0
        except Exception as e:
            x = str(e)
            print(x)

            return 1

    def undoit(self):
        try:
            path = self.path
            FileName = self.FileName
            OSX_Mod_FileName = self.OSX_Mod_FileName

            FileNameWithPath = path + '/' + FileName
            os.rename(OSX_Mod_FileName, FileNameWithPath)

            return 0
        except Exception as e:
            x = str(e)
            print(x)

            return 1

The key lines that we’ll be exploring here are as follows –

def doit()

FileNameWithPath = path + '/' + FileName
os.rename(FileNameWithPath, os.path.join(os.path.dirname(FileNameWithPath),'.'
                                         + os.path.basename(FileNameWithPath)))

In MAC or Linux, any file starts with ‘.’ will be considered as a hidden file. Hence, we’re changing the file type by doing this manipulation.

def undoit()

OSX_Mod_FileName = self.OSX_Mod_FileName

FileNameWithPath = path + '/' + FileName
os.rename(OSX_Mod_FileName, FileNameWithPath)

In this case, our application simply renaming a file with its the original file to get the file as a normal file.

Let’s understand that in Linux or MAC, you have a lot of other ways to restrict any files as it has much more granular level access control.  But, I thought, why not take a slightly different & fun way to achieve the same. After all, we’re building an Infinity War for Python verse. A little bit of fun will certainly make some sense. 🙂

5. clsProcess.py (This script will invoke any of the hide scripts, i.e. clsWinHide.py or clsOSXHide.py based on the OS platform. Hence, the name comes into the picture.)

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###########################################
#### Written By: SATYAKI DE          ######
#### Written On: 25-Jan-2019         ######
####                                 ######
#### Objective: Based on the OS, this######
#### script calls the actual script. ######
###########################################

from clsParam import clsParam as cp

plat_det = cp.config['OS_DET']

# Based on the platform
# Application is loading subprocess
# in order to avoid library missing
# case against cross platform

if plat_det == "Windows":
    import clsWinHide as win
else:
    import clsOSXHide as osx

# End of conditional class load

class clsProcess(object):
    def __init__(self):
        self.os_det = plat_det

    def doit(self):
        try:

            os_det = self.os_det
            print("OS Info: ", os_det)

            if os_det == "Windows":
                win_doit = win.clsWinHide()
                ret_val = win_doit.doit()
            else:
                osx_doit = osx.clsOSXHide()
                ret_val = osx_doit.doit()

            return ret_val
        except Exception as e:
            x = str(e)
            print(x)

            return 1

    def undoit(self):
        try:

            os_det = self.os_det
            print("OS Info: ", os_det)

            if os_det == "Windows":
                win_doit = win.clsWinHide()
                ret_val = win_doit.undoit()
            else:
                osx_doit = osx.clsOSXHide()
                ret_val = osx_doit.undoit()

            return ret_val
        except Exception as e:
            x = str(e)
            print(x)

            return 1

Key lines to explores are as follows –

from clsParam import clsParam as cp

plat_det = cp.config['OS_DET']

# Based on the platform
# Application is loading subprocess
# in order to avoid library missing
# case against cross platform

if plat_det == "Windows":
    import clsWinHide as win
else:
    import clsOSXHide as osx

This step is very essential to run the same python scripts in both the environments, e.g. in this case like MAC & Windows.

So, based on the platform details, which the application is getting from the clsParam class, it is loading the specific class to the application. And why it is so important.

Under Windows OS, this will work if you load both the class. But, under MAC, this will fail as the first program will try to load all the libraries & it may happen that the pywin32/pypiwin32 package might not available under MAC. Anyway, you are not even using that package. So, this conditional class loading is significant.

os_det = self.os_det
print("OS Info: ", os_det)

if os_det == "Windows":
    win_doit = win.clsWinHide()
    ret_val = win_doit.doit()
else:
    osx_doit = osx.clsOSXHide()
    ret_val = osx_doit.doit()

As you can see that, based on the OS, it is invoking the correct function of that corresponding class.

6. clsEnDec.py (This script will read the credentials from a csv file & then based on the salt captured from the hidden file, it will either encrypt or decrypt the content. Hence, the name comes into the picture.)

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###########################################
#### Written By: SATYAKI DE        ########
#### Written On: 25-Jan-2019       ########
#### Package Cryptography needs to ########
#### install in order to run this  ########
#### script.                       ########
####                               ########
#### Objective: This script will   ########
#### encrypt/decrypt based on the  ########
#### hidden supplied salt value.   ########
###########################################

import pandas as p
from cryptography.fernet import Fernet

class clsEnDec(object):

    def __init__(self, token):
        # Calculating Key
        self.token = token

    def encrypt_str(self):
        try:
            # Capturing the Salt Information
            salt = self.token
            # Fetching the content of lookup file
            df_orig = p.read_csv('Config_orig.csv', index_col=False)

            # Checking Individual Types inside the Dataframe
            cipher = Fernet(salt)

            df_orig['User'] = df_orig['User'].apply(lambda x1: cipher.encrypt(bytes(x1,'utf8')))
            df_orig['Pwd'] = df_orig['Pwd'].apply(lambda x2: cipher.encrypt(bytes(x2,'utf8')))

            # Writing to the File
            df_orig.to_csv('Encrypt_Config.csv', index=False)

            return 0
        except Exception as e:
            x = str(e)
            print(x)
            return 1

    def decrypt_str(self):
        try:
            # Capturing the Salt Information
            salt = self.token
            # Checking Individual Types inside the Dataframe
            cipher = Fernet(salt)

            # Fetching the Encrypted csv file
            df_orig = p.read_csv('Encrypt_Config.csv', index_col=False)

            df_orig['User'] = df_orig['User'].apply(lambda x1: str(cipher.decrypt(bytes(x1[2:-1],'utf8'))).replace("b'","").replace("'",""))
            df_orig['Pwd'] = df_orig['Pwd'].apply(lambda x2: str(cipher.decrypt(bytes(x2[2:-1],'utf8'))).replace("b'","").replace("'",""))

            # Writing to the file
            df_orig.to_csv('Decrypt_Config.csv', index=False)

            return 0
        except Exception as e:
            x = str(e)
            print(x)
            return 1

Key lines from this script are as follows –

def encrypt_str()

# Checking Individual Types inside the Dataframe
cipher = Fernet(salt)

df_orig['User'] = df_orig['User'].apply(lambda x1: cipher.encrypt(bytes(x1,'utf8')))
df_orig['Pwd'] = df_orig['Pwd'].apply(lambda x2: cipher.encrypt(bytes(x2,'utf8')))

So, once you captured the salt from that hidden file, the application is capturing that value over here. And, based on that both the field will be encrypted. But, note that cryptography package is required for this. And, you need to pass bytes value to work this thing. Hence, we’ve used bytes() function over here.

def decrypt_str()

cipher = Fernet(salt)

# Fetching the Encrypted csv file
df_orig = p.read_csv('Encrypt_Config.csv', index_col=False)

df_orig['User'] = df_orig['User'].apply(lambda x1: str(cipher.decrypt(bytes(x1[2:-1],'utf8'))).replace("b'","").replace("'",""))
df_orig['Pwd'] = df_orig['Pwd'].apply(lambda x2: str(cipher.decrypt(bytes(x2[2:-1],'utf8'))).replace("b'","").replace("'",""))

Again, in this step, our application is extracting the salt & then it retrieves the encrypted values of corresponding fields & applies the decryption logic on top of it. Note that, since we need to pass bytes value to get it to work. Hence, your output will be appended with (b’xxxxx’). To strip that, we’ve used the replace() functions. You can use regular expression using pattern matching as well.

7. callEnDec.py (This script will create the split csv files or final merge file after the corresponding process. However, this can be used as normal verbose debug logging as well. Hence, the name comes into the picture.)

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###########################################
#### Written By: SATYAKI DE           #####
#### Written On: 25-Jan-2019          #####
####                                  #####
#### Objective: Main calling function #####
###########################################

import clsEnDec as ed
import clsProcess as h
from clsParam import clsParam as cp
import time as t
import pandas as p

def main():
    print("")
    print("#" * 60)
    print("Calling (Encryption/Decryption) Package!!")
    print("#" * 60)
    print("")

    # Unhiding the file
    x = h.clsProcess()
    ret_val_unhide = x.undoit()

    if ret_val_unhide == 0:
        print("Successfully Unhide the file!")
    else:
        print("Unsuccessful to Unhide the file!")

    # To See the Unhide file
    t.sleep(10)

    print("*" * 60)
    print("Proceeding with Encryption...")
    print("*" * 60)

    # Getting Salt Value from the hidden files
    # by temporarily making it available
    FileName = cp.config['FILENAME']
    df = p.read_csv(FileName, index_col=False)
    salt = str(df.iloc[0]['Token_Salt'])
    print("-" * 60)
    print("Salt: ", salt)
    print("-" * 60)

    # Calling the Encryption Method
    x = ed.clsEnDec(salt)
    ret_val = x.encrypt_str()

    if ret_val == 0:
        print("Encryption Successful!")
    else:
        print("Encryption Failure!")

    print("")
    print("*" * 60)
    print("Checking Decryption Now...")
    print("*" * 60)

    # Calling the Decryption Method
    ret_val1 = x.decrypt_str()

    if ret_val1 == 0:
        print("Decryption Successful!")
    else:
        print("Decryption Failure!")

    # Hiding the salt file
    x = h.clsProcess()
    ret_val_hide = x.doit()

    if ret_val_hide == 0:
        print("Successfully Hide the file!")
    else:
        print("Unsuccessful to Hide the file!")

    print("*" * 60)
    print("Operation Done!")
    print("*" * 60)

if __name__ == '__main__':
    main()

And, here comes the final calling methods.

The key lines that we would like to discuss –

# Getting Salt Value from the hidden files
# by temporarily making it available
FileName = cp.config['FILENAME']
df = p.read_csv(FileName, index_col=False)
salt = str(df.iloc[0]['Token_Salt'])

As I’ve shown that, we have our hidden files that contain only 1 row & 1 column. To extract the specific value we’ve used iloc with the row number as 0 along with the column name, i.e. Token_Salt.

Now, let’s see how it runs –

Windows (64 bit):

Win_Run

Mac (32 bit):

MAC_Run

So, from the screenshot, we can see our desired output & you can calculate the aggregated value based on our sample provided in the previous screenshot.

Let’s check the Encrypted & Decrypted values –

Encrypted Values (Encrypt_Config.csv):

Encrypted_File

Decrypted Values (Decrypt_Config.csv):

Decrypted_File

So, finally, we’ve achieved our target.

I hope this will give you some more idea about more insights into the Python verse. Let me know – how do you think about this post.

Till then – Happy Avenging!

Pandas & Numpy (Space Stone of Programming World)

Today, we’ll demonstrate the different application of Pandas. In this case, we’ll be exploring the possibilities of reading large CSV files & splitting it sets of smaller more manageable csv to read.

And, after creating it, another process will merge them together. This is especially very useful when you need transformation on a large volume of data without going for any kind of memory error. And, moreover, the developer has more control over failed cases & can resume the load without restarting it from the beginning of the files.

In this case, I’ll be using one more custom methods to create the csv file instead of directly using the to_csv method of pandas.

But, before that let’s prepare the virtual environment & proceed from there –

Windows 10 (64 bit): 

Commands:

python -m venv –copies .env

.env\Scripts\activate.bat

Screenshot:

windows_screen1

Mac OS (64 bit): 

Commands:

python -m venv env

source env/bin/activate

Screenshot:

mac_screen

So, both the Windows & Mac version is 3.7 & we’re going to explore our task in the given section.

After creating this virtual environment, you need to install only pandas package for this task as shown below for both the Windows or Mac OS –

Windows:

package_install_windows

Mac:

package_install_mac

Rests are the packages comes as default with the Python 3.7.

Please find the GUI screenshots from WinSCP software comparing both the directory structures (Mac & Windows) as given below –

winscp_screen

From the above screenshot, you can see that our directory structure are not exactly identical before the blog directory. However, our program will take care of this difference.

Let’s check the scripts one-by-one,

1. clsL.py (This script will create the split csv files or final merge file after the corresponding process. However, this can be used as normal verbose debug logging as well. Hence, the name comes into the picture.)

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#############################################
#### Written By: Satyaki De              ####
#############################################
import pandas as p
import os
import platform as pl

class clsL(object):
    def __init__(self):
        self.path = os.path.dirname(os.path.realpath(__file__))

    def logr(self, Filename, Ind, df, subdir=None):
        try:
            x = p.DataFrame()
            x = df

            sd = subdir
            os_det = pl.system()

            if os_det == "Windows":
                if sd == None:
                    fullFileName = self.path + "\\" + Filename
                else:
                    fullFileName = self.path + "\\" + sd + "\\" + Filename
            else:
                if sd == None:
                    fullFileName = self.path + "/" + Filename
                else:
                    fullFileName = self.path + "/" + sd + "/" + Filename


            if Ind == 'Y':
                x.to_csv(fullFileName, index=False)

            return 0

        except Exception as e:
            y = str(e)
            print(y)
            return 3

From the above script, you can see that based on the Indicator, whose value can be either ‘Y’ or ‘N’. It will generate the csv file from the pandas data frame using to_csv method available in pandas.

Key snippet to notice –

self.path = os.path.dirname(os.path.realpath(__file__))

Here, the class is creating an instance & during that time it is initializing the value of the current path from where the application is triggering.

x = p.DataFrame()
x = df

The first line, declaring a pandas data frame variable. The second line assigns the value from the supplied method to that variable.

os_det = pl.system()

This will identify the operating system on which your application is running. Based on that, your path will be dynamically configured & passed. Hence, your application will be ready to handle multiple operating systems since beginning.

x.to_csv(fullFileName, index=False)

Finally, to_csv will generate the final csv file based on the supplied Indicator value. Also, notice that we’ve added one more parameter (index=False). By default, pandas create one extra column known as an index & maintain it’s operation based on that.

index_val

As you can see that the first column is not coming from our source files. Rather, it is generated by the pandas package in python. Hence, we don’t want to capture that in our final file by mentioning (index=False) options.

2. clsSplitFl.py (This script will create the split csv files. This will bring chunk by chunk data into your memory & process the large files.)

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#############################################
#### Written By: Satyaki De              ####
#############################################
import os
import pandas as p
import clsLog as log
import gc
import csv

class clsSplitFl(object):
    def __init__(self, srcFileName, path, subdir):
        self.srcFileName = srcFileName
        self.path = path
        self.subdir = subdir

        # Maximum Number of rows in CSV
        # in order to avoid Memory Error
        self.max_num_rows = 30000
        self.networked_directory = 'src_file'
        self.Ind = 'Y'

    def split_files(self):
        try:
            src_dir = self.path
            subdir = self.subdir
            networked_directory = self.networked_directory

            # Initiate Logging Instances
            clog = log.clsLog()

            # Setting up values
            srcFileName = self.srcFileName

            First_part, Last_part = str(srcFileName).split(".")

            num_rows = self.max_num_rows
            dest_path = self.path
            remote_src_path = src_dir + networked_directory
            Ind = self.Ind
            interval = num_rows

            # Changing work directory location to source file
            # directory at remote server
            os.chdir(remote_src_path)

            src_fil_itr_no = 1

            # Split logic here
            for df2 in p.read_csv(srcFileName, index_col=False, error_bad_lines=False, chunksize=interval):
                # Changing the target directory path
                os.chdir(dest_path)

                # Calling custom file generation method
                # to generate splitted files
                clog.logr(str(src_fil_itr_no) + '__' + First_part + '_' + '_splitted_.' + Last_part, Ind, df2, subdir)

                del [[df2]]
                gc.collect()

                src_fil_itr_no += 1

            return 0
        except Exception as e:
            x = str(e)
            print(x)

            return 1

In this script, we’re splitting the file if that file has more than 30,000 records. And, based on that it will split a number of equal or fewer volume files.

Important lines to be noticed –

self.max_num_rows = 30000

As already explained, based on this the split files contain the maximum number of rows in each file.

First_part, Last_part = str(srcFileName).split(“.”)

This will split the source file name into the first part & second part i.e. one part contains only the file name & the other part contains only the extension dynamically.

for df2 in p.read_csv(srcFileName, index_col=False, error_bad_lines=False, chunksize=interval):

As you can see, the chunk-by-chunk (mentioned as chunksize=interval) application will read lines from the large source csv. And, if it has any bad rows in the source files – it will skip them due to the following condition -> (error_bad_lines=False).

clog.logr(str(src_fil_itr_no) + ‘__’ + First_part + ‘_’ + ‘_splitted_.’ + Last_part, Ind, df2, subdir)

Dynamically generating split files in the specific subdirectory along with the modified name. So, these files won’t get overwritten – if you rerun it. Remember that the src_fil_itr_no will play an important role while merging them back to one as this is a number representing the current file’s split number.

del [[df2]]
gc.collect()

Once, you process that part – delete the data frame & deallocate the memory. So, that you won’t encounter any memory error or a similar issue.

And, the split file will look like this –

split_file_in_windows

3. clsMergeFl.py (This script will add together all the split csv files into one big csv file. This will bring chunk by chunk data into your memory & generates the large file.)

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#############################################
#### Written By: Satyaki De              ####
#############################################
import os
import platform as pl
import pandas as p
import gc
import clsLog as log
import re

class clsMergeFl(object):

    def __init__(self, srcFilename):
        self.srcFilename = srcFilename
        self.subdir = 'finished'
        self.Ind = 'Y'

    def merge_file(self):
        try:
            # Initiating Logging Instances
            clog = log.clsLog()
            df_W = p.DataFrame()
            df_M = p.DataFrame()
            f = {}

            subdir = self.subdir
            srcFilename = self.srcFilename
            Ind = self.Ind
            cnt = 0

            os_det = pl.system()

            if os_det == "Windows":
                proc_dir = "\\temp\\"
                gen_dir = "\\process\\"
            else:
                proc_dir = "/temp/"
                gen_dir = "/process/"

            # Current Directory where application presents
            path = os.path.dirname(os.path.realpath(__file__)) + proc_dir

            print("Path: ", path)
            print("Source File Initial Name: ", srcFilename)

            for fname in os.listdir(path):
                if fname.__contains__(srcFilename) and fname.endswith('_splitted_.csv'):
                    key = int(re.split('__', str(fname))[0])
                    f[key] = str(fname)

            for k in sorted(f):
                print(k)
                print(f[k])
                print("-"*30)

                df_W = p.read_csv(path+f[k], index_col=False)

                if cnt == 0:
                    df_M = df_W
                else:
                    d_frames = [df_M, df_W]
                    df_M = p.concat(d_frames)

                cnt += 1

                print("-"*30)
                print("Total Records in this Iteration: ", df_M.shape[0])

            FtgtFileName = fname.replace('_splitted_', '')
            first, FinalFileName = re.split("__", FtgtFileName)

            clog.logr(FinalFileName, Ind, df_M, gen_dir)

            del [[df_W], [df_M]]
            gc.collect()

            return 0
        except Exception as e:
            x = str(e)
            print(x)

            return 1

In this script, we’re merging smaller files into a large file. Following are the key snippet that we’ll explore –

for fname in os.listdir(path):
    if fname.__contains__(srcFilename) and fname.endswith('_splitted_.csv'):
        key = int(re.split('__', str(fname))[0])
        f[key] = str(fname)

In this section, the application will check if in that specified path we’ve files whose extension ends with “_splitted_.csv” & their first name starts with the file name initial i.e. if you have a source file named – acct_addr_20180112.csv, then it will check the first name should start with the -> “acct_addr” & last part should contain “_splitted_.csv”. If it is available, then it will start the merge process by considering one by one file & merging them using pandas data frame (marked in purple color) as shown below –

for k in sorted(f):
    print(k)
    print(f[k])
    print("-"*30)

    df_W = p.read_csv(f[k], index_col=False)

    if cnt == 0:
        df_M = df_W
    else:
        d_frames = [df_M, df_W]
        df_M = p.concat(d_frames)

    cnt += 1

Note that, here f is a dictionary that contains filename in key, value pair. The first part of the split file contains the number.  That way, it would be easier for the merge to club them back to one large file without thinking of orders.

Here, also notice the special function concat provided by the pandas. In this step, applications are merging two data frames.

Finally, the main python script, from where we’ll call it –

4. callSplitMergeFl.py

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#############################################
#### Written By: Satyaki De              ####
#############################################
import clsSplitFl as t
import clsMergeFl as cm
import re
import platform as pl
import os

def main():
    print("Calling the custom Package for large file splitting..")
    os_det = pl.system()

    print("Running on :", os_det)

    ###############################################################
    ###### User Input based on Windows OS                  ########
    ###############################################################

    srcF = str(input("Please enter the file name with extension:"))
    base_name = re.sub(r'[0-9]','', srcF)
    srcFileInit = base_name[:-5]

    if os_det == "Windows":
        subdir = "\\temp\\"
        path = os.path.dirname(os.path.realpath(__file__)) + "\\"
    else:
        subdir = "/temp/"
        path = os.path.dirname(os.path.realpath(__file__)) + '/'

    ###############################################################
    ###### End Of User Input                                 ######
    ###############################################################

    x = t.clsSplitFl(srcF, path, subdir)

    ret_val = x.split_files()

    if ret_val == 0:
        print("Splitting Successful!")
    else:
        print("Splitting Failure!")

    print("-"*30)

    print("Finally, Merging small splitted files to make the same big file!")

    y = cm.clsMergeFl(srcFileInit)

    ret_val1 = y.merge_file()

    if ret_val1 == 0:
        print("Merge Successful!")
    else:
        print("Merge Failure!")

    print("-"*30)



if __name__ == "__main__":
    main()

Following are the key section that we can check –

import clsSplitFl as t
import clsMergeFl as cm

Like any other standard python package, we’re importing our own class into our main callable script.

x = t.clsSplitFl(srcF, path, subdir)
ret_val = x.split_files()

Or,
y = cm.clsMergeFl(srcFileInit)
ret_val1 = y.merge_file()

In this section, we’ve instantiated the class & then we’re calling its function. And, based on the return value – we’re printing the status of our application last run.

The final run of this application looks like ->

Windows:

final_run_windows

Mac:

final_run_mac

And, the final file should look like this –

Windows:

win_img1

MAC:

mac_img1

Left-hand side representing windows final processed/output file, whereas right-hand side representing MAC final processed/output file.

Hope, this will give you some idea about how we can use pandas in various cases apart from conventional data computing.

In this post, I skipped the exception part intentionally. I’ll post one bonus post once my series complete.

Let me know, what do you think.

Till then, Happy Avenging!

Satyaki De

How to store data from XML to Tables

In the previous post we have discussed about generating an XML file using Oracle SQL XML functions. Today we will do that in reverse manner. That means we will load the data generated by that query in the database tables.

At the end of this post (Which is a continue of the previous post) – you will be successfully generate an XML file from Oracle Tables & also able to load the data from XML on that same structured tables. So, that will complete the full life cycle of XML in oracle(Obviously concentrate on some basics).

Lets see –

Our main ingredients for this class – is the XML file named – emp_oracle.xml

And, it looks like –




200
<
First>Whalen</First>
4400
1987-09-17


201
<
First>Billy</First>
4500
1985-06-10


202
<
First>Bireswar</First>
9000
1978-06-10


We need to create one Oracle Directories to map with the Operating System directories in the following manner ->

sys@ORCL>
sys@ORCL>select * from v$version;

BANNER
----------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.1.0.6.0 - Production
PL/SQL Release 11.1.0.6.0 - Production
CORE 11.1.0.6.0 Production
TNS for 32-bit Windows: Version 11.1.0.6.0 - Production
NLSRTL Version 11.1.0.6.0 - Production

Elapsed: 00:00:00.00
sys@ORCL>
sys@ORCL>
sys@ORCL>CREATE OR REPLACE DIRECTORY SATY_DIR AS 'D:\XML_Output'
2 /

Directory created.

Elapsed: 00:00:00.23
sys@ORCL>
sys@ORCL>GRANT READ, WRITE ON DIRECTORY SATY_DIR TO SCOTT, HR;

Grant succeeded.

Elapsed: 00:00:00.08
sys@ORCL>

Once you have created the directory successfully and give the proper privileges to the users like Scott or Hr – you have completed one important component of today’s test. Still we are far to go. Now the second part is –

scott@ORCL>
scott@ORCL>select * from v$version;

BANNER
--------------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.1.0.6.0 - Production
PL/SQL Release 11.1.0.6.0 - Production
CORE 11.1.0.6.0 Production
TNS for 32-bit Windows: Version 11.1.0.6.0 - Production
NLSRTL Version 11.1.0.6.0 - Production

Elapsed: 00:00:00.00
scott@ORCL>
scott@ORCL>
scott@ORCL>CREATE TABLE t
2 (
3 serialNo NUMBER(10),
4 fileName VARCHAR2(100),
5 xml XMLTYPE,
6 constraints pk_serialNo primary key(serialNo)
7 );

Table created.

Elapsed: 00:00:04.13
scott@ORCL>
scott@ORCL>
scott@ORCL>CREATE SEQUENCE x_seq
2 START WITH 1
3 INCREMENT BY 1;

Sequence created.

Elapsed: 00:00:00.31
scott@ORCL>
scott@ORCL>CREATE OR REPLACE PROCEDURE load_xml(
2 p_dir IN VARCHAR2,
3 p_filename IN VARCHAR2
4 )
5 IS
6 l_bfile BFILE := BFILENAME(p_dir, p_filename);
7 l_clob CLOB;
8 BEGIN
9 DBMS_LOB.createtemporary (l_clob, TRUE);
10
11 DBMS_LOB.fileopen(l_bfile, DBMS_LOB.file_readonly);
12 DBMS_LOB.loadfromfile(l_clob, l_bfile, DBMS_LOB.getlength(l_bfile));
13 DBMS_LOB.fileclose(l_bfile);
14
15 INSERT INTO t(
16 serialNo,
17 fileName,
18 xml
19 )
20 VALUES (
21 x_seq.NEXTVAL,
22 p_filename,
23 XMLTYPE.createXML(l_clob)
24 );
25
26 COMMIT;
27
28 DBMS_LOB.freetemporary(l_clob);
29 END;
30 /

Procedure created.

Elapsed: 00:00:00.88
scott@ORCL>
scott@ORCL>EXEC load_xml(p_dir => 'SATY_DIR', p_filename => 'emp_oracle.xml');

PL/SQL procedure successfully completed.

Elapsed: 00:00:00.16
scott@ORCL>
scott@ORCL>set long 5000
scott@ORCL>
scott@ORCL>set pagesize 0
scott@ORCL>
scott@ORCL>select xml from t;



200
Whalen
4400
1987-09-17


201
Billy
4500
1985-06-10


202
Bireswar
9000
1978-06-10




Elapsed: 00:00:00.10
scott@ORCL>

Ok. So, we’ve initially load the data into the temp table t. But, we need to load the data from this temp table t to our target table revive_xml which will look like –

scott@ORCL>create table revive_xml
2 (
3 rev_emp_id number(4),
4 rev_f_name varchar2(40),
5 rev_salary number(10,2),
6 rev_jn_dt date,
7 constraints pk_rev_emp_id primary key(rev_emp_id)
8 );

Table created.

Elapsed: 00:00:00.40
scott@ORCL>

Ok. So, we have done another important part of our job. Let’s concentrate on our final mission –

scott@ORCL>insert into revive_xml(
2 rev_emp_id,
3 rev_f_name,
4 rev_salary,
5 rev_jn_dt
6 )
7 select cast(t1.EmployeeId as number(4)) EmployeeId,
8 t2.FirstName,
9 cast(t3.Salary as number(10,2)) Salary,
10 to_date(t4.JoiningDt,'YYYY-MM-DD') JoiningDt
11 from (
12 select rownum rn1,
13 extractValue(value(EmployeeId),'/Emp/Employee_ID') EmployeeId
14 from t,
15 table(xmlsequence(extract(xml, '/EmployeeList/Emp'))) EmployeeId
16 ) t1,
17 (
18 select rownum rn2,
19 extractValue(value(FirstName),'/Emp/First') FirstName
20 from t,
21 table(xmlsequence(extract(xml, '/EmployeeList/Emp'))) FirstName
22 ) t2,
23 (
24 select rownum rn3,
25 extractValue(value(Salary),'/Emp/Sal') Salary
26 from t,
27 table(xmlsequence(extract(xml, '/EmployeeList/Emp'))) Salary
28 ) t3,
29 (
30 select rownum rn4,
31 extractValue(value(HireDate),'/Emp/HireDate') JoiningDt
32 from t,
33 table(xmlsequence(extract(xml, '/EmployeeList/Emp'))) HireDate
34 ) t4
35 where t1.rn1 = t2.rn2
36 and t1.rn1 = t3.rn3
37 and t1.rn1 = t4.rn4;

3 rows created.

Elapsed: 00:00:00.16
scott@ORCL>
scott@ORCL>commit;

Commit complete.

Elapsed: 00:00:00.22
scott@ORCL>
scott@ORCL>
scott@ORCL>select * from revive_xml;

REV_EMP_ID REV_F_NAME REV_SALARY REV_JN_DT
---------- ---------------------------------------- ---------- ---------
200 Whalen 4400 17-SEP-87
201 Billy 4500 10-JUN-85
202 Bireswar 9000 10-JUN-78

scott@ORCL>

So, you have done it finally.

You can do it another way but that is limited to single record parsing –

scott@ORCL>with t
2 as (
3 select xmlType('
4
5
6 200
7 Whalen
8 4400
9 1987-09-17
10
11 ') xml from dual
12 )
13 SELECT rownum rn,
14 a.EmployeeId,
15 a.FirstName,
16 a.Salary,
17 a.JoiningDt
18 FROM t,
19 XMLTABLE('/EmployeeList'
20 PASSING t.xml
21 COLUMNS
22 EmployeeId varchar2(10) PATH '/EmployeeList/Emp/Employee_ID',
23 FirstName varchar2(20) PATH '/EmployeeList/Emp/First',
24 Salary number(10) PATH '/EmployeeList/Emp/Sal',
25 JoiningDt date PATH '/EmployeeList/Emp/HireDate'
26 ) a;

RN EMPLOYEEID FIRSTNAME SALARY JOININGDT
---------- ---------- -------------------- ---------- ---------
1 200 Whalen 4400 17-SEP-87

scott@ORCL>
scott@ORCL>

Hope this will solve your purpose.

Also you can refer to the following XML In Oracle link.

Regards.