selenium项目实战（三）：实现网页验证码识别

截屏整个页面获得验证码坐标数据根据坐标数据抠图使用pytesseract模块进行验证 问题：

利用save_screenshot和PIL模块的crop截取验证码区域时，截取不到正确的二维码图片。
**原因：**坐标定位不准确，电脑默认缩放的值为125%。将其改为100%即可正确定位；或者将对应的左上角坐标x、y，图片宽高width、height分别乘以对应的比例1.25，同样可以准确截取图片。

图片验证码识别方案：

使用pytesseract库：该方法适合各种变形较少的验证码，对于扭曲的字母和数字识别率大大降低。调用showapi 提供的 图片验证码识别自己训练机器学习模型实现验证码识别。

import pickle
import string
import time
from lib.ShowapiRequest import ShowapiRequest
from PIL import Image
import os
import random
import base64


def get_code(driver, id):
    # 获取验证码图片
    t = time.time()
    path = os.path.dirname(os.path.dirname(__file__)) + '\screenshots'
    picture_name1 = path + '\' + str(t) + '.png'
    driver.save_screenshot(picture_name1)
    ce = driver.find_element_by_id(id)
    left = ce.location['x']
    top = ce.location['y']
    right = ce.size['width'] + left
    down = ce.size['height'] + top

    dpr = driver.execute_script('return window.devicePixelRatio')

    im = Image.open(picture_name1)
    img = im.crop((left * dpr, top * dpr, right * dpr, down * dpr))

    t = time.time()
    picture_name2 = path + '\' + str(t) + '.png'
    img.save(picture_name2)
    with open(picture_name2, "rb") as fs:
        # b64encode：编码，b64decode: 解码
        base64_data = base64.b64encode(fs.read())
        # base64.b64decode(base64_data)

    r = ShowapiRequest("http://route.showapi.com/2360-2", "927638", "1a0681c845114fbf9beaa7a666c6eb82")
    r.addBodyPara("file_base64", base64_data)
    res = r.post()
    text = res.json()['showapi_res_body']
    code = text['pic_str']

    return code


# 生成随机字符串
def gen_random_str():
    rand_str = ''.join(random.sample((string.ascii_letters + string.digits), 8))  # 随机生成8位的字母+数字组合字符
    return rand_str


def save_cookie(driver, path):
    with open(path, 'wb') as filehandler:
        cookies = driver.get_cookies()
        print(cookies)
        pickle.dump(cookies, filehandler)


def load_cookie(driver, path):
    with open(path, 'rb') as cookiesfile:
        cookies = pickle.load(cookiesfile)
        for cookie in cookies:
            driver.add_cookie(cookie)