Below is a short python script that allows users to save searched images to local drive using Image search on Google. It requires Selenium as Google requires users to press the “show more results” button and the scroll bar to move all the way to the bottom of page for more images to be displayed. Using Selenium will be an easier choice for this function.

The below python script will have the following:

1. Enable users to input multiple search keywords either by entry or get from file. Users can leave the program to download on its own after creating a series of search keywords.
2. Based on each keyword, form the google search url. Most of the parameters inside the google search url can be fixed. The only part that required changing is the search keyword as highlighted below in red.
   • https://www.google.com.sg/search?q=things+to+type+into+google&espv=2&biw=1920&bih=989&site=webhp&source=lnms&tbm=isch&sa=X&ei=ApZZVdrQJcqWuATcz4K4Cw&sqi=2&ved=0CAcQ_AUoAg
3. Run google search and obtain page source for the images. This is run using Selenium. To obtain the full set of images, Selenium will help to press the button and scroll the scrollbar to bottom of pages so that Google can load the remaining images. There seems to be a hard quota of 1000 pics for image search on Google.
4. Use python pattern and xpath to retrieve the corresponding url for each image. The xpath will use the following tag:
   • tag_list = dom(‘a.rg_l’) #a tag with class = rg_l
5. Based on each url, it will check the following before downloading the image file:
   • whether there is any redirect of site. This is done using Python Pattern redirect function.
   • check the extension whether it is a valid image file type.
6. The image files are downloaded to a local folder (generated by date). Each image will be label according to the search key and a counter. There will be a corresponding text file mapping the image label to the image url for reference.

import re, os, sys, datetime, time
import pandas
from selenium import webdriver
from contextlib import closing
from selenium.webdriver import Firefox
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.common.by import By
from selenium.webdriver.support import expected_conditions as EC

from pattern.web import URL, extension, cache, plaintext, Newsfeed, DOM

class GoogleImageExtractor(object):

    def __init__(self, search_key = '' ):
        """ Google image search class
            Args:
                search_key to be entered.

        """
        if type(search_key) == str:
            ## convert to list even for one search keyword to standalize the pulling.
            self.g_search_key_list = [search_key]
        elif type(search_key) == list:
            self.g_search_key_list = search_key
        else:
            print 'google_search_keyword not of type str or list'
            raise

        self.g_search_key = ''

        ## user options
        self.image_dl_per_search = 200

        ## url construct string text
        self.prefix_of_search_url = "https://www.google.com.sg/search?q="
        self.postfix_of_search_url = '&source=lnms&tbm=isch&sa=X&ei=0eZEVbj3IJG5uATalICQAQ&ved=0CAcQ_AUoAQ&biw=939&bih=591'# non changable text
        self.target_url_str = ''

        ## storage
        self.pic_url_list = []
        self.pic_info_list = []

        ## file and folder path
        self.folder_main_dir_prefix = r'C:\data\temp\gimage_pic'

    def reformat_search_for_spaces(self):
        """
            Method call immediately at the initialization stages
            get rid of the spaces and replace by the "+"
            Use in search term. Eg: "Cookie fast" to "Cookie+fast"

            steps:
            strip any lagging spaces if present
            replace the self.g_search_key
        """
        self.g_search_key = self.g_search_key.rstrip().replace(' ', '+')

    def set_num_image_to_dl(self, num_image):
        """ Set the number of image to download. Set to self.image_dl_per_search.
            Args:
                num_image (int): num of image to download.
        """
        self.image_dl_per_search = num_image

    def get_searchlist_fr_file(self, filename):
        """Get search list from filename. Ability to add in a lot of phrases.
            Will replace the self.g_search_key_list
            Args:
                filename (str): full file path
        """
        with open(filename,'r') as f:
            self.g_search_key_list = f.readlines()

    def formed_search_url(self):
        ''' Form the url either one selected key phrases or multiple search items.
            Get the url from the self.g_search_key_list
            Set to self.sp_search_url_list
        '''
        self.reformat_search_for_spaces()
        self.target_url_str = self.prefix_of_search_url + self.g_search_key +\
                                self.postfix_of_search_url

    def retrieve_source_fr_html(self):
        """ Make use of selenium. Retrieve from html table using pandas table.

        """
        driver = webdriver.Firefox()
        driver.get(self.target_url_str)

        ## wait for log in then get the page source.
        try:
            driver.execute_script("window.scrollTo(0, 30000)")
            time.sleep(2)
            self.temp_page_source = driver.page_source
            #driver.find_element_by_css_selector('ksb _kvc').click()#cant find the class
            driver.find_element_by_id('smb').click() #ok
            time.sleep(2)
            driver.execute_script("window.scrollTo(0, 60000)")
            time.sleep(2)
            driver.execute_script("window.scrollTo(0, 60000)")

        except:
            print 'not able to find'
            driver.quit()

        self.page_source = driver.page_source

        driver.close()

    def extract_pic_url(self):
        """ extract all the raw pic url in list

        """
        dom = DOM(self.page_source)
        tag_list = dom('a.rg_l')

        for tag in tag_list[:self.image_dl_per_search]:
            tar_str = re.search('imgurl=(.*)&imgrefurl', tag.attributes['href'])
            try:
                self.pic_url_list.append(tar_str.group(1))
            except:
                print 'error parsing', tag

    def multi_search_download(self):
        """ Mutli search download"""
        for indiv_search in self.g_search_key_list:
            self.pic_url_list = []
            self.pic_info_list = []

            self.g_search_key = indiv_search

            self.formed_search_url()
            self.retrieve_source_fr_html()
            self.extract_pic_url()
            self.downloading_all_photos() #some download might not be jpg?? use selnium to download??
            self.save_infolist_to_file()

    def downloading_all_photos(self):
        """ download all photos to particular folder

        """
        self.create_folder()
        pic_counter = 1
        for url_link in self.pic_url_list:
            print pic_counter
            pic_prefix_str = self.g_search_key  + str(pic_counter)
            self.download_single_image(url_link.encode(), pic_prefix_str)
            pic_counter = pic_counter +1

    def download_single_image(self, url_link, pic_prefix_str):
        """ Download data according to the url link given.
            Args:
                url_link (str): url str.
                pic_prefix_str (str): pic_prefix_str for unique label the pic
        """
        self.download_fault = 0
        file_ext = os.path.splitext(url_link)[1] #use for checking valid pic ext
        temp_filename = pic_prefix_str + file_ext
        temp_filename_full_path = os.path.join(self.gs_raw_dirpath, temp_filename )

        valid_image_ext_list = ['.png','.jpg','.jpeg', '.gif', '.bmp', '.tiff'] #not comprehensive

        url = URL(url_link)
        if url.redirect:
            return # if there is re-direct, return

        if file_ext not in valid_image_ext_list:
            return #return if not valid image extension

        f = open(temp_filename_full_path, 'wb') # save as test.gif
        print url_link
        self.pic_info_list.append(pic_prefix_str + ': ' + url_link )
        try:
            f.write(url.download())#if have problem skip
        except:
            #if self.__print_download_fault:
            print 'Problem with processing this data: ', url_link
            self.download_fault =1
        f.close()

    def create_folder(self):
        """
            Create a folder to put the log data segregate by date

        """
        self.gs_raw_dirpath = os.path.join(self.folder_main_dir_prefix, time.strftime("_%d_%b%y", time.localtime()))
        if not os.path.exists(self.gs_raw_dirpath):
            os.makedirs(self.gs_raw_dirpath)

    def save_infolist_to_file(self):
        """ Save the info list to file.

        """
        temp_filename_full_path = os.path.join(self.gs_raw_dirpath, self.g_search_key + '_info.txt' )

        with  open(temp_filename_full_path, 'w') as f:
            for n in self.pic_info_list:
                f.write(n)
                f.write('\n')

if __name__ == '__main__':

    choice =4

    if choice ==4:
        """test the downloading of files"""
        w = GoogleImageExtractor('')#leave blanks if get the search list from file
        searchlist_filename = r'C:\data\temp\gimage_pic\imgsearch_list.txt'
        w.set_num_image_to_dl(200)
        w.get_searchlist_fr_file(searchlist_filename)#replace the searclist
        w.multi_search_download()