Output all the email body of the email group searched by Gmail and narrowed down

Introduction

Since the document output function of gmail that was in Labs of Gmail has disappeared, I tried to write it easily with python using Gmail API of Google Apps.

Preparation

Read the following documentation to get client_secret.json.

• https://developers.google.com/gmail/api/quickstart/python

All you have to do is define the application and download it, so you can do it in about a minute.

Installation

Install api client with pip.

$ pip install --upgrade google-api-python-client

Sample code

In the case of the above address example, it ends with the output of the label, so add the code to get the message body.

sample.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

# from __future__ import print_function
import httplib2
import os
import base64
import logging
import traceback

from apiclient import discovery
import oauth2client
from oauth2client import client
from oauth2client import tools

try:
    import argparse
    flags = argparse.ArgumentParser(parents=[tools.argparser]).parse_args()
except ImportError:
    flags = None

SCOPES = 'https://www.googleapis.com/auth/gmail.readonly'
CLIENT_SECRET_FILE = 'client_secret.json'
APPLICATION_NAME = 'Gmail API Python Quickstart'


def get_credentials():
    """Gets valid user credentials from storage.

    If nothing has been stored, or if the stored credentials are invalid,
    the OAuth2 flow is completed to obtain the new credentials.

    Returns:
        Credentials, the obtained credential.
    """
    home_dir = os.path.expanduser('~')
    credential_dir = os.path.join(home_dir, '.credentials')
    if not os.path.exists(credential_dir):
        os.makedirs(credential_dir)
    credential_path = os.path.join(
        credential_dir,
        'gmail-python-quickstart.json'
    )

    store = oauth2client.file.Storage(credential_path)
    credentials = store.get()
    if not credentials or credentials.invalid:
        flow = client.flow_from_clientsecrets(CLIENT_SECRET_FILE, SCOPES)
        flow.user_agent = APPLICATION_NAME
        if flags:
            credentials = tools.run_flow(flow, store, flags)
        else:  # Needed only for compatibility with Python 2.6
            credentials = tools.run(flow, store)
        print('Storing credentials to ' + credential_path)
    return credentials


def extract_message(service, message):
    try:
        msg_obj = service.users().messages().get(userId='me', id=message['id'], format='raw').execute()
        return base64.urlsafe_b64decode(msg_obj['raw'].encode('ASCII'))
    except:
        logging.error(traceback.format_exc())


def extract_message_body(service, message):
    try:
        email_str = extract_message(service, message)
        subject_idx = email_str.find('Subject:')
        body_idx = email_str[subject_idx:].find(os.linesep)
        return email_str[subject_idx + body_idx:].strip()
    except:
        logging.error(traceback.format_exc())


def main():
    """Shows basic usage of the Gmail API.

    Creates a Gmail API service object and outputs a list of label names
    of the user's Gmail account.
    """
    credentials = get_credentials()
    http = credentials.authorize(httplib2.Http())
    service = discovery.build('gmail', 'v1', http=http)

    results = service.users().messages().list(userId='me', q="").execute()
    print results
    messages = results.get('messages', [])

    if not messages:
        print 'No messages found.'
    else:
        print 'messages:'
        for message in messages:
            print 'message body: ', extract_message_body(service, message)


if __name__ == '__main__':
    main()

The search keyword is thrown into q of the list function as a character string. The format is the same as the gmail search.