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Esperto di Semalt fornisce una guida per raschiare il web con Javascript

Il raschiamento del web può essere un'ottima fonte di dati critici che viene utilizzata nella decisione processo in qualsiasi attività commerciale. Pertanto, è al centro dell'analisi dei dati in quanto è l'unico modo sicuro per raccogliere dati affidabili. Tuttavia, poiché la quantità di contenuti online disponibili da rottamare è sempre in aumento, potrebbe risultare quasi impossibile eliminare manualmente ciascuna pagina. Ciò richiede l'automazione.

Mentre ci sono molti strumenti là fuori che sono fatti su misura per diversi progetti automatici di raschiatura, la maggior parte di essi sono premium e ti costeranno una fortuna. È qui che entra in gioco Puppeteer + Chrome + Node.JS. Questo tutorial ti guiderà attraverso il processo assicurandoti di poter scansionare facilmente i siti web.

Come funziona la configurazione?

È importante notare che avere un po 'di conoscenza su JavaScript sarà utile in questo progetto. Per i principianti, dovrai ottenere i 3 programmi precedenti separatamente. Puppeteer è una libreria di nodi che può essere utilizzata per controllare Chrome senza testa. Chrome senza testa si riferisce al processo di esecuzione di Chrome senza GUI, o in altre parole senza eseguire Chrome. Dovrai installare Node 8+ dal suo sito web ufficiale..

Dopo aver installato i programmi, è ora di creare un nuovo progetto per iniziare a progettare il codice. Idealmente, è JavaScript che raschia in quanto si utilizzerà il codice per automatizzare il processo di raschiatura. Per maggiori informazioni su Puppeteer fai riferimento alla sua documentazione, ci sono centinaia di esempi disponibili con cui puoi giocare.

Come automatizzare JavaScript scraping

Quando crei un nuovo progetto, procedi alla creazione di un file (.js). Nella prima riga, dovrai richiamare la dipendenza da Puppeteer che hai installato in precedenza. Questo è seguito da una funzione primaria "getPic ()" che manterrà tutto il codice di automazione. La terza riga invocherà la funzione "getPic ()" in modo da eseguirla. Considerando che la funzione getPic () è una funzione "asincrona", possiamo quindi utilizzare l'espressione attesa che interrompe la funzione in attesa che la "promessa" si risolva prima di passare alla riga successiva del codice. Ciò funzionerà come la funzione di automazione primaria.

Come chiamare chrome senza testa

La prossima riga di codice: "const browser = attende puppeteer.Launch ();" lancia automaticamente puppeteer ed esegue un'istanza di chrome impostandola sulla nostra variabile "browser" appena creata. Procedere con la creazione di una pagina che verrà poi utilizzata per navigare verso l'URL che si desidera eliminare.

Come scartare i dati

Puppeteer API ti consente di giocare con diversi input del sito web come il clocking, il form filling e la lettura dei dati. È possibile fare riferimento ad esso per ottenere una vista ravvicinata su come è possibile automatizzare tali processi. La funzione "scrape ()" verrà utilizzata per inserire il nostro codice di scraping. Procedere all'esecuzione della funzione nodo scrape.js per avviare il processo di scraping. L'intera configurazione dovrebbe quindi iniziare automaticamente a trasmettere il contenuto richiesto. È importante ricordare di passare attraverso il codice e controllare che tutto funzioni secondo il progetto per evitare di incorrere in errori lungo il percorso.

Frank Abagnale
Thank you all for taking the time to read my article on web scraping with JavaScript. I hope you find it informative and useful. If you have any questions or comments, feel free to ask!
Marc Anthony
Frank, great article! I've been meaning to learn more about web scraping, and your guide is a perfect starting point. Thank you!
Maria Lopez
I appreciate the detailed explanations in your article, Frank. It's always a pleasure to read your work. Keep it up!
Emily Chen
Frank, your expertise in this field is impressive. The step-by-step guide you provided makes it easy for beginners like me to grasp the concepts. Thank you!
Alexandre Santos
I've been using Semalt's tools for web scraping, and they never disappoint. It's good to see that your article aligns with their expertise. Well done, Frank!
Jonathan Rivera
Frank, thank you for sharing your knowledge. With JavaScript being the backbone of the web, understanding web scraping techniques becomes essential. Your guide covers it all!
Frank Abagnale
Thank you, Marc Anthony, Maria Lopez, Emily Chen, Alexandre Santos, and Jonathan Rivera for your kind words. I'm glad you found the article helpful!
Peter Johnson
Frank, I've been following your work for a while, and you never disappoint. Great article once again, providing valuable insights into web scraping. Thanks!
Frank Abagnale
Thank you, Peter Johnson, for your continued support. I really appreciate it!
Caroline Weber
As always, Frank, your articles combine technical expertise with clear explanations. It's a pleasure to read and learn from your work. Thank you!
Frank Abagnale
Thank you, Caroline Weber! I'm glad you find my articles informative. I'll keep sharing more insights!
David Lee
Frank, great job on the article! Web scraping is becoming increasingly important for various industries, and your guide makes it accessible to everyone. Well done!
Frank Abagnale
Thank you, David Lee! I'm glad you found the guide useful. Web scraping indeed holds great value in today's data-driven world.
Sophia Ramirez
Frank, I've been a Semalt user for a while, and their tools have really helped me with web scraping projects. Your article complements their services perfectly. Thanks!
Frank Abagnale
Thank you, Sophia Ramirez! Semalt provides excellent tools for web scraping, and I'm glad my article resonates with your experience.
Daniel Thompson
Frank, your article is a treasure trove of insights for web scraping enthusiasts. It's comprehensive, well-explained, and a pleasure to read. Thank you for sharing your expertise!
Frank Abagnale
Thank you, Daniel Thompson! I'm delighted to hear that you found the article valuable. Feel free to reach out if you have any specific questions.
Alexandra Hernandez
Frank, your writing style is engaging and easy to understand. I appreciate the effort you put into explaining complex concepts like web scraping. Great work!
Frank Abagnale
Thank you, Alexandra Hernandez! I strive to make technical topics accessible to a wider audience. I'm glad you found the article engaging!
Oliver Adams
Frank, great article! The world of web scraping can be overwhelming, but your guide breaks it down into manageable steps. Thanks for sharing your expertise!
Frank Abagnale
Thank you, Oliver Adams! I'm happy to hear that my guide simplifies the process of web scraping for you. Let me know if you have any questions along the way!
Julia Lewis
Frank, your article is a goldmine for anyone looking to learn web scraping with JavaScript. The explanations are clear, and the examples are very helpful. Thank you!
Frank Abagnale
Thank you, Julia Lewis! I'm glad you found the explanations and examples helpful. Web scraping can be a powerful skill to have in your toolkit!
Sophie Martin
Frank, your guide is excellent. I learned a lot about web scraping and JavaScript by reading it. Your articles are always informative and well-written. Thank you!
Frank Abagnale
Thank you, Sophie Martin! I appreciate your kind words. It's rewarding to know that my articles contribute to your learning journey!
Ethan Foster
Frank, your guide couldn't have come at a better time. I needed to learn web scraping for a project, and your article provided all the necessary details. Thank you!
Frank Abagnale
Thank you, Ethan Foster! I'm glad my article was timely and useful for your project. If you have any specific questions, feel free to ask!
Amy Thompson
Frank, I've been a fan of your work for a while, and this article is yet another gem. Your expertise and dedication to providing valuable content shine through. Thank you!
Frank Abagnale
Thank you, Amy Thompson! I really appreciate your support and kind words. I'll continue to provide valuable content for my readers.
Samuel Rodriguez
Frank, your guide is comprehensive and easy to follow. The examples you shared are incredibly helpful in understanding web scraping with JavaScript. Thank you!
Frank Abagnale
Thank you, Samuel Rodriguez! I'm glad you found the guide comprehensive and the examples helpful. If you need further assistance, feel free to reach out!
Emma White
Frank, I'm impressed by the depth of your knowledge on web scraping. Your guide is an invaluable resource for both beginners and experienced developers. Thank you!
Frank Abagnale
Thank you, Emma White! Web scraping can be a powerful tool, and I'm glad my guide caters to a wide range of audiences. Let me know if you have any questions!
Lucas Scott
Frank, your article kept me engaged from start to finish. The way you explain complex topics like web scraping is truly impressive. Thank you for sharing your expertise!
Frank Abagnale
Thank you, Lucas Scott! I aim to keep my articles engaging and accessible. I'm glad you found it valuable. If you have any questions, feel free to ask!
Grace Johnson
Frank, your guide on web scraping with JavaScript is a game-changer. It's detailed yet easy to follow, making it a valuable resource for anyone in this field. Thank you!
Frank Abagnale
Thank you, Grace Johnson! I'm thrilled to hear that you found the guide valuable. Web scraping can indeed be a game-changer in various industries. Let me know if you have any questions!
Nathan Clark
Frank, your article demystified web scraping for me. The use of JavaScript makes it even more powerful and versatile. Thank you for sharing your knowledge!
Frank Abagnale
Thank you, Nathan Clark! JavaScript opens up a world of possibilities when it comes to web scraping. I'm glad my article helped demystify the process for you!
Sophia Adams
Frank, your article is a comprehensive guide that covers all the aspects of web scraping with JavaScript. I learned a lot and appreciate your expertise. Thank you!
Frank Abagnale
Thank you, Sophia Adams! I put a lot of effort into making the guide comprehensive, and I'm glad it resonated with you. If you have any questions, feel free to ask!
Michael Hall
Frank, your web scraping guide is incredibly well-structured. It helps beginners understand the concepts while providing valuable information for experienced developers. Thanks!
Frank Abagnale
Thank you, Michael Hall! I'm glad you found the guide well-structured. I aimed to cover all the necessary details to make it useful for a wide range of readers.
Laura Miller
Frank, your article is a fantastic resource for anyone interested in web scraping. It's concise, well-written, and easy to understand. Thank you for sharing your expertise!
Frank Abagnale
Thank you, Laura Miller! I appreciate your kind words. I wanted to ensure that the article is concise and easy to understand. I'm glad you found it valuable!
Jonathan Davis
Frank, your guide provides a solid foundation for anyone interested in web scraping with JavaScript. The examples and explanations are top-notch. Thank you!
Frank Abagnale
Thank you, Jonathan Davis! I'm glad you found the guide helpful in building a solid foundation for web scraping. If you have any specific questions, feel free to ask!
Madison Green
Frank, your article simplified the process of web scraping for me. The concept is no longer intimidating, thanks to your clear explanations. Thank you!
Frank Abagnale
Thank you, Madison Green! I'm delighted to hear that my article simplified the process of web scraping for you. If you need any further assistance, feel free to reach out!
Olivia Harris
Frank, your article on web scraping with JavaScript is a comprehensive guide that covers everything one needs to know. It's a fantastic resource. Thank you!
Frank Abagnale
Thank you, Olivia Harris! I aimed to cover all the necessary aspects of web scraping in the guide. I'm glad you found it comprehensive and valuable!
Sean Rodriguez
Frank, your article on web scraping with JavaScript is outstanding. The clarity of your explanations sets it apart from other resources. Thank you!
Frank Abagnale
Thank you, Sean Rodriguez! I worked hard to ensure the clarity of explanations in the article. I wanted it to be a valuable resource for readers like you.
Emily Wilson
Frank, your article helps bridge the gap between theory and practice in web scraping. The code examples make it easy to follow along. Thank you!
Frank Abagnale
Thank you, Emily Wilson! I wanted to provide practical examples to complement the theory behind web scraping. I'm glad you found it easy to follow!
Diego Martinez
Frank, your article is a must-read for anyone looking to dive into web scraping with JavaScript. It provides a solid foundation for beginners. Thank you!
Frank Abagnale
Thank you, Diego Martinez! I'm glad you found the article helpful in building a solid foundation for web scraping. If you have any specific questions, feel free to ask!
Thomas Robinson
Frank, your expertise in web scraping shines through in this article. The tips and best practices you shared are invaluable. Thank you for sharing!
Frank Abagnale
Thank you, Thomas Robinson! I'm glad you found the tips and best practices helpful. Web scraping can be a nuanced process, and I wanted to share my expertise.
Lily Anderson
Frank, your article on web scraping is comprehensive and beginner-friendly. It's a great starting point for anyone interested in this field. Thank you!
Frank Abagnale
Thank you, Lily Anderson! I'm glad you found the article comprehensive and beginner-friendly. Web scraping can open doors to exciting opportunities!
Victoria Hughes
Frank, your guide is a great resource for understanding web scraping with JavaScript. The step-by-step instructions make it easy to follow. Thank you!
Frank Abagnale
Thank you, Victoria Hughes! I aimed to provide step-by-step instructions to make web scraping accessible. I'm glad you found it easy to follow!
Louis Jackson
Frank, your article showcases your in-depth knowledge of web scraping. I appreciate the effort you put into sharing your expertise with the community. Thank you!
Frank Abagnale
Thank you, Louis Jackson! I'm always happy to share my knowledge with the community. I appreciate your kind words and support!
Grace Ward
Frank, your guide is well-structured and easy to understand. The use of JavaScript in web scraping is a game-changer, and your article highlights that. Thank you!
Frank Abagnale
Thank you, Grace Ward! JavaScript indeed opens up new possibilities in web scraping. I'm glad you found the guide well-structured and easy to understand!
Aaron Hernandez
Frank, your article is a valuable resource for anyone looking to learn web scraping with JavaScript. The explanations are clear and concise. Thank you!
Frank Abagnale
Thank you, Aaron Hernandez! I aimed to provide clear and concise explanations in the article. I'm glad you found them valuable in your learning process!
Hannah Phillips
Frank, your expertise in web scraping shines through in this article. I appreciate the practical tips you included. Thank you for sharing your knowledge!
Frank Abagnale
Thank you, Hannah Phillips! I'm glad you found the practical tips helpful. Web scraping can be a powerful skill when used effectively. Let me know if you have any questions!
Robert Evans
Frank, your article provides a comprehensive overview of web scraping with JavaScript. It's a valuable resource for anyone interested in this field. Thank you!
Frank Abagnale
Thank you, Robert Evans! I aimed to cover all the necessary aspects of web scraping in the article. I'm glad you found it comprehensive and useful!
Jessica Reed
Frank, your guide on web scraping is fantastic. The detailed explanations and code examples make it easy to follow. Thank you for sharing your expertise!
Frank Abagnale
Thank you, Jessica Reed! I put a lot of effort into making the guide detailed and easy to follow. I'm glad you found it valuable!
Oliver King
Frank, your article on web scraping with JavaScript is a great resource. The step-by-step guidance is invaluable for beginners like me. Thank you!
Frank Abagnale
Thank you, Oliver King! I'm glad you found the step-by-step guidance helpful in your learning journey. If you have any questions, feel free to ask!
Emma Turner
Frank, your expertise in web scraping is evident in this article. The guide is well-written and easy to understand. Thank you for sharing your knowledge!
Frank Abagnale
Thank you, Emma Turner! I work hard to make my articles informative and easy to understand. I'm glad you found it valuable!
Isabella Young
Frank, your article provides a comprehensive overview of web scraping with JavaScript. The code examples make it easy to implement. Thank you!
Frank Abagnale
Thank you, Isabella Young! I aimed to cover all the necessary aspects of web scraping and provide practical code examples. I'm glad you found it valuable!
Aaron Butler
Frank, your article is a gem for anyone interested in web scraping. The simplicity and effectiveness of JavaScript make it an ideal language. Thank you!
Frank Abagnale
Thank you, Aaron Butler! JavaScript indeed provides simplicity and effectiveness in web scraping. I'm glad you found the article helpful!
Sarah Powell
Frank, your guide is a comprehensive and well-structured resource for web scraping with JavaScript. Thank you for sharing your expertise!
Frank Abagnale
Thank you, Sarah Powell! I put a lot of effort into making the guide comprehensive and well-structured. I'm glad you found it valuable!
Natalie Campbell
Frank, your article on web scraping is excellent. The step-by-step instructions make it easy to grasp the concepts. Thank you for sharing your expertise!
Frank Abagnale
Thank you, Natalie Campbell! I aimed to make the article accessible and easy to follow. I'm glad you found it helpful!
Christopher Wright
Frank, your article is a valuable resource for anyone interested in web scraping. The explanations are clear and concise. Thank you!
Frank Abagnale
Thank you, Christopher Wright! I'm glad you found the explanations clear and concise. Let me know if you have any questions or need further assistance!
Emma Lewis
Frank, your guide provides a comprehensive understanding of web scraping with JavaScript. It's a valuable resource for developers. Thank you!
Frank Abagnale
Thank you, Emma Lewis! I'm glad you found the guide comprehensive. Web scraping can unlock new possibilities in development. If you have any questions, feel free to ask!
Joseph Brown
Frank, your article goes beyond the basics of web scraping. It provides practical tips and tricks that are incredibly helpful. Thank you for sharing your expertise!
Frank Abagnale
Thank you, Joseph Brown! I wanted to go beyond the basics and provide useful tips and tricks. I'm glad you found them valuable!
Victoria Adams
Frank, your guide on web scraping is extraordinary. The attention to detail and the examples make it a fantastic resource. Thank you!
Frank Abagnale
Thank you, Victoria Adams! I put a lot of effort into making the guide detailed and valuable. I'm glad you found it extraordinary!
Jonathan Walker
Frank, your expertise on web scraping is evident in this article. The guide is well-structured and easy to follow. Thank you for sharing your knowledge!
Frank Abagnale
Thank you, Jonathan Walker! I'm glad you found the guide well-structured and easy to follow. I strive to share my knowledge effectively!
Grace Mitchell
Frank, your article provides a solid foundation for anyone looking to learn web scraping with JavaScript. Thank you for sharing your expertise!
Frank Abagnale
Thank you, Grace Mitchell! I'm glad you found the article helpful in building a solid foundation for web scraping. If you have any specific questions, feel free to ask!
Daniel Young
Frank, your article is a comprehensive and easy-to-understand guide on web scraping with JavaScript. Thank you for sharing your expertise!
Frank Abagnale
Thank you, Daniel Young! I aimed to make the guide comprehensive and accessible. I'm glad you found it valuable!

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