Instant php web scraping pdf

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    Simply use your login credentials for immediate access. Table of Contents Preface 1 Instant PHP Web Scraping 5 Preparing your development environment . Free PHP eBooks. Contribute to manithchhuon/the-best-php-books development by creating an account on GitHub. Get up and running with the basic techniques of web scraping using PHP.

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    Instant Php Web Scraping Pdf

    Filled with practical, step-by-step instructions and clear explanations for the most important and useful tasks. Short, concise recipes to learn a variety of useful. Web scraping is the process of extracting and creating a structured representa- tion of data from a web site. HTML 3 Web Scraping using Approximate Tree Pattern Matching. Basic The immediate consequence is the same for the. The necessity to scrape web sites and PDF documents .. 6 .. Motto → Instantly turn web pages into data. Indubitably, this is one of.

    Errata Although we have taken every care to ensure the accuracy of our content, mistakes do happen. By doing so, you can save other readers from frustration and help us improve subsequent versions of this book. Piracy Piracy of copyright material on the Internet is an ongoing problem across all media. At Packt, we take the protection of our copyright and licenses very seriously. If you come across any illegal copies of our works, in any form, on the Internet, please provide us with the location address or website name immediately so that we can pursue a remedy. Please contact us at copyright packtpub. We appreciate your help in protecting our authors, and our ability to bring you valuable content. Questions You can contact us at questions packtpub. Web scraping is the process of programmatically crawling and downloading information from websites and extracting unstructured or loosely structured data into a structured format. This book assumes the reader has no previous knowledge of programming and will guide the reader through the basic techniques of web scraping through a series of short practical recipes using PHP, including preparing your development environment, scraping HTML elements using XPath, using regular expressions for pattern matching, developing custom scraping functions, crawling through pages of a website, including submitting forms and cookie-based authentication; logging in to e-mail accounts and extracting content, and saving scraped data in a relational database using MySQL. The book concludes with a recipe in which a class is built, using the information learned in previous recipes, which can be reused for future scraping projects and extended upon as the reader expands their knowledge of the technology. This is free to download, install, and use. The essentials we will require are as follows: f An Integrated development environment IDE for writing our code and managing projects. PHP is the programming language we will be using, for executing our code. However, we will be installing the XAMPP package, which includes all of these, along with an additional software, for example Apache server, which will come handy in the future if you develop your scraper further.

    That way you can also track the efficiency of your various methods to improve the rank. Or go one step further and offer your customers a graph for all their websites and keywords which shows how well your work has influenced the ranks.

    Search Engine Scraper source code

    Or go even one more step further and analyze the ranks of hundreds of thousands worldwide companies. You may also make the whole project interactive for users, let them get ranks or charts according to their keywords and websites. Of course this project can also be used to just brute force get massive amounts of URLs, titles according to a set of keywords.

    By doing regular scrape runs and putting the results into a database with timestamp you can unleash the real power of this project, if you need help to develop such extensions I am ready for hire. Google would ban any user who tries to automatically scrape their search engine results.

    In the worst case they can throw out a ban which blocks ten thousands of IP addresses permanently. This is usually all that happens, it threatens the project but not the legal entity behind it. However there is also a legal threat. If you do not accept the search engine TOS you should not have legal threats with passively scraping it. To make sure about that you need to consult your local lawyer. In any case it is possible to avoid getting detected, the free Search Engine Scraper on this website can be used longterm without detection.

    The Google Search Scraper from here already contains code to detect, detection and abort in that case. There are different typical error messages Google issues when it decided to block or slow down activity. Here are two examples: We're sorry To protect our users, we can't process your request right now. We'll restore your access as quickly as possible, so try again soon. In the meantime, if you suspect that your computer or network has been infected, you might want to run a virus checker or spyware remover to make sure that your systems are free of viruses and other spurious software.

    We apologize for the inconvenience, and hope we'll see you again on Google. We're sorry If you're continually receiving this error, you may be able to resolve the problem by deleting your Google cookie and revisiting Google. For browser-specific instructions, please consult your browser's online support center. If your entire network is affected, more information is available in the Google Web Search Help Center.

    This is a worst case scenario, if you stick to the peak rates and use IPs from us-proxies. The benefit of using us-proxies. However, the code is not limited to this particular service. You are free to adapt the source to suit your needs. You can either make an agreement with us-proxies for IP addresses or replace the relevant parts and use your own IP solution.

    Before using the source code please read the license agreement. Ranking information for keyword "Scraping PHP"! Rank [Type] - Website - Title! Traversing multiple pages Intermediate , explains topics such as identifying pagination, navigating through multiple pages, and associating scraped data with its source page.

    Scheduling scrapes Simple , discusses how to schedule the execution of scraping scripts for complete automation. Building a reusable scraping class Advanced , introduces basic object oriented programming OOP principles to build a scraping class, which can be expanded upon and reused for future web scraping projects. Bonus recipes covers topics such as how to recognize a pattern using regular expressions, how to verify the scraped data, how to retrieve and extract content from e-mails, and how to implement multithreaded scraping using multi-cURL.

    These recipes are available at http: Who this book is for This book is aimed at those who are new to web scraping, with little or no previous programming experience. Here are some examples of these styles, and an explanation of their meaning. Code words in text are shown as follows: Words that you see on the screen, in menus or dialog boxes for example, appear in the text like this: Tips and tricks appear like this. Reader feedback Feedback from our readers is always welcome.

    Let us know what you think about this book—what you liked or may have disliked. Reader feedback is important for us to develop titles that you really get the most out of. To send us general feedback, simply send an e-mail to feedback packtpub. If there is a topic that you have expertise in and you are interested in either writing or contributing to a book, see our author guide on www.

    Customer support Now that you are the proud owner of a Packt book, we have a number of things to help you to get the most from your download. If you downloadd this book elsewhere, you can visit http: Errata Although we have taken every care to ensure the accuracy of our content, mistakes do happen.

    If you find a mistake in one of our books—maybe a mistake in the text or the code—we would be grateful if you would report this to us. By doing so, you can save other readers from frustration and help us improve subsequent versions of this book. If you find any errata, please report them by visiting http: Once your errata are verified, your submission will be accepted and the errata will be uploaded on our website, or added to any list of existing errata, under the Errata section of that title.

    Any existing errata can be viewed by selecting your title from http: Piracy Piracy of copyright material on the Internet is an ongoing problem across all media. At Packt, we take the protection of our copyright and licenses very seriously. If you come across any illegal copies of our works, in any form, on the Internet, please provide us with the location address or website name immediately so that we can pursue a remedy.

    Please contact us at copyright packtpub.

    We appreciate your help in protecting our authors, and our ability to bring you valuable content. Questions You can contact us at questions packtpub. Web scraping is the process of programmatically crawling and downloading information from websites and extracting unstructured or loosely structured data into a structured format. This book assumes the reader has no previous knowledge of programming and will guide the reader through the basic techniques of web scraping through a series of short practical recipes using PHP, including preparing your development environment, scraping HTML elements using XPath, using regular expressions for pattern matching, developing custom scraping functions, crawling through pages of a website, including submitting forms and cookie-based authentication; logging in to e-mail accounts and extracting content, and saving scraped data in a relational database using MySQL.

    The book concludes with a recipe in which a class is built, using the information learned in previous recipes, which can be reused for future scraping projects and extended upon as the reader expands their knowledge of the technology. This is free to download, install, and use. Instant PHP Web Scraping Getting ready Before we can get to work developing our scraping tools, we first need to prepare our development environment.

    The essentials we will require are as follows: PHP is the programming language we will be using, for executing our code. However, we will be installing the XAMPP package, which includes all of these, along with an additional software, for example Apache server, which will come handy in the future if you develop your scraper further.

    After installing these tools, we will adjust the necessary system settings and test that everything is working correctly. How to do it Now, let's take a look at how to prepare our development environment, by performing the following steps: Once the file has been downloaded, unzip the contents. The resulting directory, eclipse-php, is the eclipse program folder.

    Drag-and-drop this into the C: Upon successful installation, start XAMPP for the first time and select the following components to install: Save in the default destination. Click on Install and the chosen programs will install. Click on the Start button for Apache. With the necessary software and tools installed, we need to set our PHP path variable. In the left menu bar click on Advanced system settings.

    In the System Properties window select the Advanced tab, and click on the Environment variables In the Environment Variables window there are two lists, User variables and System variables.

    In the System variables list, scroll down to the row for the Path variable. Select the row and click on the Edit button.

    Downloading the example code You can download the example code files for all Packt books you have downloadd from your account at http: In the textbox for variable's value: The PHP directory will now be in our path variables. Find the following line and remove the semicolon from the beginning of it: Save the file and close the text editor. We can now test whether the installation is working correctly by opening our web browser and visiting http: The final step is to create a new project in Eclipse and execute our program.

    We start Eclipse by navigating to the folder in which we saved it earlier and double- clicking on the eclipse-php icon. We are asked to select our Workspace. Browse to our xampp directory and then navigate to htdocs, for example C: Leave all of the settings as they are and name our project as Web Scraping. Click on Next, and then click on Finish. Now we are ready to write our first script and execute it. Enter the following code into Eclipse, as show in the following screenshot: We will see the text Hello world!

    Let's look at how we performed the previously defined steps in detail: After installing our required software, we set our PHP path variable. This ensures that we can execute PHP directly from the command line by typing php rather than having to type the full location of our PHP executable file, every time we wish to execute it.

    Using the final set of steps, we set up Eclipse, and then create a small PHP program which echoes the text Hello world! When we visit a web page in a client, such as a web browser, an HTTP request is sent. The server then responds by delivering the requested resource, for example an HTML file, to the browser, which then interprets the HTML and renders it on screen, according to any associated styling specification.

    When we make a cURL request, the server responds in the same way, and we receive the source code of the Web page which we are then free to do with as we will in this case perform by scraping the data we require from the page. Getting ready In this recipe we will use cURL to request and download a web page from a server. Refer to the Preparing your development environment recipe.

    What is web scraping – Part 1 – Beginner’s guide

    Enter the following code into a new PHP project: Save the project as 2-curl-request. Execute the script. Once our script has completed, we will see the source code of http: How it works Let's look at how we performed the previously defined steps: All the PHP code should appear between these two tags. Running through the code inside the curlGet function, we start off by initializing a new cURL session as follows: We then set our options for cURL as follows: Now that the cURL request has been made and we have the results, we close the cURL session by using the following code: After the function is closed we are able to use it throughout the rest of our script.

    Later, deciding on the URL we wish to request, http: There are a number of different HTTP request methods which indicate the server the desired response, or the action to be performed.

    This tells the server that we would like to retrieve a resource. Depending on the resource we are requesting, a number of parameters may be passed in the URL.

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    For example, when we perform a search on the Packt Publishing website for a query, say, php, we notice that the URL is http: This is requesting the resource books the page that displays search results and passing a value of php to the keys parameter, indicating that the dynamically generated page should show results for the search query php.

    Though we will cover many more throughout the course of this book, some other options to be aware of, that you may wish to try out, are listed in the following table: Since rv: Some common response code values are as follows: OK ff Moved Permanently ff Bad Request ff Unauthorized ff Forbidden ff Not Found ff Internal Server Error It is often useful to have our scrapers responding to different response code values in a different manner, for example, letting us know if a web page has moved, or is no longer accessible, or we are unauthorized to access a particular page.

    XPath can be used to navigate through elements in an XML document.

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    Save the project as 3-xpath-scraping. We will see the results of our scrape displayed on the screen, as follows: Integrate your existing data and web services with Ext JS data support. Extend Ext JS through custom components. Let's look at how these steps were performed: Firstly, we have included the curlGet function that we created in the Making a simple cURL request recipe , which enables us to reuse this functionality to request the URL we are going to scrape.

    The code inside the function is as follows: This instructs the procedure to execute without throwing errors. This is necessary, because in almost every case, an HTML file on the Web will contain an invalid markup.

    This is an unavoidable reality, so we wish to ignore any errors found that would otherwise cause our script to fail.

    We then execute the curlGet function, passing our URL, http: With our resource downloaded, we can now convert it to an XPath DOM object in order to scrape our required data from it.

    We do this by calling our returnXPathObject function, passing our resource as a parameter by using the following code: If we take a look at the source code of the page we are scraping, http: Firstly, we'll scrape the title of the book. The author details are scraped similarly to the previous data, though, because there are multiple items, both the XPath expression and the code required to add them to our array are slightly different.

    Some important expressions to know are listed in the following table: Gives the current node.. In these cases custom functions are useful for scraping our required data from the page. The custom function, which we will create in this recipe, scrapeBetween , will enable us to scrape the content from between any two known strings in a document.

    Save the project as 5-custom-scraping-functions. The results of the scrape will be displayed on screen as follows: UA How it works Next we have our scrapeBetween function which takes the following three parameters: This parameter is a string which indicates until which place we wish to scrape 2. If either of them are not, the function ends and returns false as shown in the following code: With our necessary functions defined, we can now do some scraping.

    This is then echoed to the screen using the following code: In these cases we need to request the file, download it, and verify that it is an image and save it to a local directory for future use. Using the cURL library and file functions in PHP, in this recipe we will create a function that will be used to download and save images from a target site. Save the project as 7-scraping-images. The downloaded image will now be stored in the same directory as the script.

    Firstly, we have included the curlGet function that we created in the Making a simple cURL request recipe, giving us the functionality to request a target page. With our required functions now in place, we can go ahead and scrape an image from our target page, in this case the cover of a book.

    As we have done in previous recipes, we request a target page, return an XPath object of that page, and from there we scrape the URL of the image we wish to save by using the following code: With the URL of our required image we can extract the name of the image by using the PHPs explode function to separate the parts of the URL into an array, and then use the end function to return only the last element, which will be the name of the image as given in the following code: If it returns true, we request the image file using the curlGet function as follows: While the scraper we have created in this recipe has to download an image by changing the validation, this can even be used to download files of any type from a target website.

    Submitting a form using cURL Intermediate Many times while web scraping, the data which we require is located behind a form. Whether that be a login form to a members area, a search form, a file upload, or any other form submission, it is frequently implemented using a POST request. There are a number of steps required to successfully submit a POST form, such as capturing and analyzing HTTP headers, submitting the form, and in case of a login form, using cookies to store session data.

    Save the project as 8-submitting-form. We are now logged in to the website. If you have followed the recipes in this book, specifically the Making a simple cURL request recipe, then the first part of this script should look familiar.

    The parameters passed to the function is the URL to the form fields to POST, and a success string which will be used to check whether the form is submitted correctly by following the given steps: Inside the curlPost function, we first set a user agent string. This is used to identify our client to the server. We can enter any string here to use as our user agent, which would usually be the name of our crawler. In this case, we have chosen to emulate a popular browser, though this can sometimes be seen as deceitful when crawling parts of the Web, which we do not own as explained in the following code: Next, as we are logging into a website which uses cookies for authentication, we need to set a file to store our cookies in by using the following code: We have introduced some new cURL settings here as follows: Finally, the function with which we check if the login was successful.

    To do this, we first need to identify a string on the page that is displayed upon successful login. The existence of this is then checked using strpos , and if it is found, then login has been successful and the page is returned; if it is not found then the function returns FALSE as given in the following code: We first assign our username and password to variables as follows:

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