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Web Scraping & Bots · レッスン

ブラウザー操作の自動化

クリック、スクロール、フォーム送信、要素の読み込み待ちなどのユーザー操作をプログラムで再現します。

「ブラウザー操作の自動化」はCoddyKit上の無料Web Scraping & Botsレッスンです。 これはレッスン2/4です。 下記で完全なレッスンを無料で読むことができます。その後、ブラウザ内の組み込みコードエディタと24時間対応のAIチューターでハンズオン演習できます。 これはWeb Scraping & Bots学習パスの一部であり、ウェブとCoddyKitアプリ全体で進捗が同期されます。 Web Scraping & Botsコースには全4レッスンが含まれています。

このレッスンの一部はまだ翻訳されておらず、英語で表示されています。

Automate Browser Actions

In the previous lesson, we introduced Selenium for handling dynamic web content. Now, let's learn how to make our bots interact with web pages!

We'll simulate real user actions like clicking buttons, typing into forms, and scrolling, making our scrapers much more powerful.

Locate Elements First

Before you can interact with an element (like a button or a text box), you need to find it on the page. Selenium provides several ways to do this.

You'll use methods like find_element(By.ID, "some_id") or find_element(By.CLASS_NAME, "some_class") to pinpoint your target.

  • By.ID: Unique ID attribute.
  • By.NAME: Name attribute.
  • By.CLASS_NAME: CSS class.
  • By.XPATH: Powerful path expressions.
  • By.CSS_SELECTOR: CSS selector syntax.

Making a Click

The most common interaction is clicking. Whether it's a button, a link, or a checkbox, the .click() method does the job.

After finding an element, just call .click() on it. This simulates a user's mouse click.

Try clicking a fictitious button:

from selenium import webdriver
from selenium.webdriver.common.by import By
import time

def main():
    driver = webdriver.Chrome() # Or Firefox, Edge, etc.
    driver.get("https://www.example.com")
    try:
        # Imagine a button with ID 'myButton'.
        # On example.com, we can click the 'More information...' link.
        more_info_link = driver.find_element(By.LINK_TEXT, "More information...")
        more_info_link.click()
        print("Clicked 'More information...' link.")
        time.sleep(2) # To see the new page
    finally:
        driver.quit()

if __name__ == "__main__":
    main()

Entering Text

To fill out forms or search bars, you use the .send_keys() method. This simulates typing text into an input field.

You can also send special keys like Keys.ENTER, Keys.TAB, etc., from selenium.webdriver.common.keys.

Let's type into a search box:

from selenium import webdriver
from selenium.webdriver.common.by import By
import time

def main():
    driver = webdriver.Chrome()
    driver.get("https://www.google.com") # Using google for a search box
    try:
        search_box = driver.find_element(By.NAME, "q")
        search_box.send_keys("CoddyKit Selenium")
        time.sleep(2) # See the typed text
    finally:
        driver.quit()

if __name__ == "__main__":
    main()

Sending Form Data

After filling out a form, you often need to submit it. You can do this in a couple of ways:

  • Click the submit button: submit_button.click()
  • Call .submit() on any input element within the form: input_field.submit()

The .submit() method is convenient as it doesn't require finding the specific submit button.

Example of submitting a form (after typing):

from selenium import webdriver
from selenium.webdriver.common.by import By
import time

def main():
    driver = webdriver.Chrome()
    driver.get("https://www.google.com")
    try:
        search_box = driver.find_element(By.NAME, "q")
        search_box.send_keys("Selenium forms")
        search_box.submit() # Submits the form containing this element
        time.sleep(3) # Observe search results
    finally:
        driver.quit()

if __name__ == "__main__":
    main()

Why We Need to Wait

Web pages often load content dynamically using JavaScript. This means elements might not be immediately available when Selenium tries to find them.

If your script tries to interact with an element that hasn't loaded yet, it will throw an error. This is where "waits" come in!

Waits tell Selenium to pause execution until a certain condition is met or a timeout occurs.

Simple Implicit Waits

An implicit wait tells the WebDriver to poll the DOM (Document Object Model) for a certain amount of time when trying to find an element.

If the element is not immediately available, the driver will wait for the specified duration before throwing a NoSuchElementException.

It's a global setting for the entire driver session:

from selenium import webdriver
import time

def main():
    driver = webdriver.Chrome()
    # Set implicit wait for 10 seconds
    driver.implicitly_wait(10)
    try:
        driver.get("https://www.example.com")
        print("Implicit wait set for 10 seconds.")
        # Any subsequent find_element calls will wait up to 10s
        # if the element isn't immediately found.
        time.sleep(2) # Just to show the wait is active
    finally:
        driver.quit()

if __name__ == "__main__":
    main()

Precise Explicit Waits

Explicit waits are more powerful and flexible. They allow you to define a specific condition to wait for, rather than a fixed time.

You use WebDriverWait in combination with expected_conditions (often imported as EC) to specify what you're waiting for. This is best for specific elements and dynamic content.

Here's how to wait for a (fictional) element with ID 'dynamicDiv' to be visible:

from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
import time

def main():
    driver = webdriver.Chrome()
    driver.get("https://www.example.com")
    try:
        print("Waiting for an element to be visible...")
        # WebDriverWait waits up to 10 seconds
        # for an element with ID 'dynamicDiv' to become visible.
        # This element does not exist on example.com, so it will timeout.
        # In a real app, replace with a real ID.
        element = WebDriverWait(driver, 10).until(
            EC.visibility_of_element_located((By.ID, "dynamicDiv"))
        )
        print(f"Element found: {element.text}")
    except Exception as e:
        print(f"Element not found or timed out: {e}")
    finally:
        driver.quit()

if __name__ == "__main__":
    main()

Scrolling for More Content

Some websites load content as you scroll down (infinite scroll). To access this content, your bot needs to scroll the page.

You can use JavaScript execution to scroll to a specific position or to the bottom of the page.

To scroll to the very bottom:

from selenium import webdriver
import time

def main():
    driver = webdriver.Chrome()
    driver.get("https://www.wikipedia.org") # A page that can be scrolled
    try:
        # Scroll down to the bottom of the page
        driver.execute_script("window.scrollTo(0, document.body.scrollHeight);")
        print("Scrolled to the bottom of the page.")
        time.sleep(2) # Observe the scroll
        # You can also scroll incrementally:
        # driver.execute_script("window.scrollBy(0, 500);")
    finally:
        driver.quit()

if __name__ == "__main__":
    main()

Interacting with Select Menus

HTML <select> elements (dropdown menus) require a special approach in Selenium using the Select class.

First, find the <select> element, then create a Select object, and finally use methods like select_by_visible_text(), select_by_value(), or select_by_index().

Example:

from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import Select
import time

def main():
    driver = webdriver.Chrome()
    # For this example, we'll use a test page with a dropdown.
    # In a real scenario, you'd navigate to a specific URL.
    driver.get("https://www.selenium.dev/selenium/web/formPage.html")
    try:
        # Find the select element by its ID
        select_element = driver.find_element(By.ID, "selectMenu")
        select = Select(select_element)
        
        # Select an option by its visible text
        select.select_by_visible_text("Example select text")
        print("Selected 'Example select text' by visible text.")
        time.sleep(2)
        
        # Select an option by its value attribute
        select.select_by_value("2")
        print("Selected option with value '2'.")
        time.sleep(2)

    finally:
        driver.quit()

if __name__ == "__main__":
    main()

Test Your Knowledge

You've learned about automating various browser interactions and the crucial role of waits.

Which of the following are valid ways to interact with web elements using Selenium in Python?

Recap: Automating Interactions

Well done! You now know how to make your Selenium bots perform common user actions:

  • Finding Elements: Using various By strategies.
  • Interacting: .click() for buttons/links, .send_keys() for text input, and .submit() for forms.
  • Waiting: Essential for dynamic content, using implicitly_wait() or more precise WebDriverWait with expected_conditions.
  • Advanced: Scrolling with JavaScript and handling dropdowns with the Select class.

These skills are fundamental for building robust web automation scripts!

よくある質問

「ブラウザー操作の自動化」レッスンは無料ですか?

はい。「ブラウザー操作の自動化」の完全なテキストはこのウェブで無料で読めます。インタラクティブに演習し(組み込みコードエディタと24時間対応のAIチューター)、Web Scraping & Botsコースの残りをアンロックするには、CoddyKit PROにアップグレードしてください。 Web Scraping & Botsコースには全4レッスンが含まれています。

「ブラウザー操作の自動化」で何を学びますか?

クリック、スクロール、フォーム送信、要素の読み込み待ちなどのユーザー操作をプログラムで再現します。 ブラウザで直接実行するハンズオンコードでWeb Scraping & Botsを演習し、24時間対応のAIチューターがレッスンを進める中での質問に答えます。

Web Scraping & Botsを始めるのに経験は必要ですか?

事前経験は必要ありません。CoddyKitのWeb Scraping & Botsは初級者から上級者向けに構成されているため、ここから始めるか最初から始めて、自分のペースで進むことができます。 これはレッスン2/4です。

「ブラウザー操作の自動化」レッスンにはどのくらい時間がかかりますか?

ほとんどのCoddyKitレッスンは約5~10分かかります。各レッスンはコンパクトでインタラクティブなので、着実に進歩し、ウェブとアプリ全体で正確に前回の場所から再開できます。

このWeb Scraping & Botsレッスンでコードを書いて実行できますか?

はい。すべてのWeb Scraping & Botsレッスンに組み込みコードエディタが含まれているため、ブラウザでリアルコードを書いて実行し、即座のAIフィードバックを取得できます。ローカル設定は不要です。

このコースのすべてのレッスン

  1. Selenium入門
  2. ブラウザー操作の自動化
  3. JavaScriptからのデータ抽出
  4. 動的ページの待機戦略
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