Tự học HTML và CSS trong 1 giờ - part 70 ppt

ptg The most common relational database offered by web hosting providers is MySQL, an open source database that’s freely available. There are many other popular relational databases, too, including Oracle, Microsoft SQL Server, and PostgreSQL (another free database). For web applications, however, MySQL is the leader. All the applications I’m going to discuss in particular work with MySQL. If you want to read more about it, the manual is available online at http://dev.mysql.com/doc/. Deploying Applications All the applications discussed in this lesson run on a web server. When it comes to hosted applications, you don’t need to worry about the web server. That’s the job of the application provider. In cases where you are installing your own applications, it’s up to you to make sure your web server environment will work with your application. For example, all the applications I’m going to discuss in detail are written in PHP. If you are planning on deploying to a server running Microsoft Internet Information Services with- out PHP support, you won’t get these applications to run. Before you download and attempt to install an application, check its requirements to make sure the server on which you plan to deploy the application meets them. If you lease server space from a web hosting provider, you may need to check with it before installing your software to make sure it’s compatible with their environment. For example, in addition to big requirements such as PHP or MySQL, some software pack- ages also require particular libraries or supplemental software packages to function prop- erly. You might need to ask to find out whether your hosting provider has all the software you need running in its environment. In some cases, a hosting provider will actually install the software you need if you explain what you’re trying to do. There’s another issue you might run into depending on what kind of access you have to your server. Generally, two levels of access are available when it comes to web providers: FTP access and shell access. If you have FTP access, you’re allowed to upload your files to the server, but you are not allowed to log in to the server and run commands directly. Shell access provides a command-line interface to the server that enables you to edit files directly on the server, move things around, and generally use the server more like it’s your own computer. If you don’t have shell access to the server, you will have to edit the configuration files for your application locally on your own computer and then upload the files and test them on the server. 666 LESSON 22: Content Management Systems and Publishing Platforms Download from www.wowebook.com ptg TypePad: A Hosted Blogging Application As I’ve said before, the shortest route to using a content management system is to sign up for a hosted application. You don’t have to download the application, deal with a host- ing provider, run installation scripts, or tweak configuration files. TypePad is a subscrip- tion service for publishing a blog. It provides all the features you’d expect from a blog—archives, user comments, and syndication feeds. You can use it without supplying your own domain name, as long as you’re willing to accept a name that ends with “type- pad.com,” and you don’t even have to modify the templates if one of the default themes is okay with you. As soon as you’ve signed up for TypePad, you can start posting articles to your new blog. Figure 22.1 shows a screenshot of the TypePad posting interface. It’s fairly typical of the posting interfaces in most content management systems. For blogs, the typical properties of an article are title, category, and the article text. You can enter all those val- ues in this form. TypePad also includes some basic workflow features. You can publish the post immediately, save it as a draft, or schedule it to be published at a specific time. TypePad: A Hosted Blogging Application 667 22 FIGURE 22.1 The TypePad pub- lishing interface. To write a post and publish it, you just have to fill in the fields and click the Save button. At that point, your post will appear on the public web page for your blog, as shown in Figure 22.2. Download from www.wowebook.com ptg 668 LESSON 22: Content Management Systems and Publishing Platforms FIGURE 22.2 A public post on a weblog. Even for a relatively basic service such as TypePad, there are still a lot of configuration options. Figure 22.3 shows TypePad’s blog configuration page. As you can see from the figure, TypePad’s Control Panel has several tabs, all of which reveal various configura- tion options. This is one difference between hosted applications and applications you install and maintain. Generally, applications that you install include configuration files that you must edit, along with configuration forms like the ones found in TypePad. FIGURE 22.3 The TypePad author profile con- figuration page. Download from www.wowebook.com ptg One more thing to discuss regarding TypePad is how to modify the design for your pages. TypePad allows you to change both the theme and the layout for your pages. Themes alter the color scheme and visual appearance of your pages. Layouts dictate where the various components of the page are placed, such as the blog entries, links to the archive, photo galleries, and other pieces of content you publish. TypePad includes a set of themes you can choose from, as shown in Figure 22.4. WordPress 669 22 FIGURE 22.4 Selecting a theme in TypePad. If you prefer to design something, TypePad provides that option, too. The degree of flex- ibility you have in modifying your design depends on which level of TypePad account you sign up for. Users with Pro accounts can edit the style sheet for their blog directly. There are several other subscription (and free) blog services, too, including WordPress.com (http://www.wordpress.com), Tumblr (http://www.tumblr.com), and Blogger (http://www.blogger.com). They all offer feature sets similar to TypePad. WordPress WordPress is a blog publishing tool written in PHP. It’s open source software, so you are free to use it or modify it as you want. You can download WordPress at http://word- press.org/. The first step is to extract the file in the place where you want to install your blog. The files in the archive are all inside a folder called wordpress, but you can move them into another directory if you like. Download from www.wowebook.com ptg FIGURE 22.5 WordPress needs a configuration file to get started. 670 LESSON 22: Content Management Systems and Publishing Platforms Many Web hosting providers offer one-click installation of WordPress and other popular content management systems from their control panels. If you want to use WordPress, or any of the applications discussed in this lesson, you should check to see if your hosting provider offers this feature. After you’ve extracted the archive, you should copy the wordpress directory to a direc- tory accessible as part of your website. If you want your blog to reside at the root direc- tory for your server, copy the files out of the wordpress folder and directly into your document root directory. Visiting the home page of your WordPress installation will quickly illustrate the difference between using a hosted service and running an applica- tion on your own. You’re greeted with a request to create a configuration file, as shown in Figure 22.5. TIP In your WordPress directory, you’ll find a file named wp-config-sample.php. To set up WordPress, you need to copy this file to a file named wp-config.php and enter your database settings. If you are deploying WordPress to a server where you don’t have a shell account and can’t edit files directly, you must create and edit this file before you upload your files to the server. I’m installing WordPress on my own computer, so I created the database and database user myself. If you are installing WordPress on a shared hosting account, chances are you’ve gotten the database login information from your hosting provider. In some cases, you may want to install several different applications, or perhaps even multiple installa- tions of WordPress in the same database. In that case, you’ll want to look at the follow- ing line in wp-config.php: $table_prefix = ‘wp_’; // Only numbers, letters, and underscores please! Download from www.wowebook.com ptg This is the string that WordPress puts on the front of the names of all the files it creates. If you already have one WordPress installation using a database, you’ll want to change this prefix to something else so as to prevent the two installs from conflicting. I have cre- ated a database just for this purpose, so I’ll leave the prefix as is. After you have wp-config.php in place, you can proceed with the installation. If you reload the index page in the WordPress directory, you’ll be referred to install.php, unless there’s a problem with your database configuration. If WordPress can’t connect to the database using the settings you provided, it will print an error message. Make sure you have all the information on your database entered properly and test your database connection using this page until WordPress stops complaining. In the first step of the actual installation, shown in Figure 22.6, you pick a name for your blog, create an administrative user, and enter your email address. After you’ve done that, WordPress creates all the database tables it needs and generates an account for you to log into the system. That’s it for installation. WordPress 671 22 FIGURE 22.6 The WordPress installation page. After you’ve completed the installation, you’re presented with the Dashboard for your blog. It’s not all that different from the Control Panel for TypePad. The posting page, shown in Figure 22.7, is even more similar to TypePad and most other blogging tools. You can enter the title and body of your post, along with some other optional informa- tion. The options on the right side enable you to mark your post as draft or published as well as categorize it. You can select from other options, too. Download from www.wowebook.com ptg FIGURE 22.7 The posting page for WordPress. 672 LESSON 22: Content Management Systems and Publishing Platforms The posting page isn’t all that interesting. Where WordPress differs from TypePad is in how much control you have over the layout and design of your blog. With WordPress, all the work you’ve done learning HTML, CSS, and PHP can pay off. Clicking the Appearance menu item and then clicking Editor enables you to edit all the files that make up the published side of your blog from within your browser (see Figure 22.8). FIGURE 22.8 Editing part of a WordPress theme. You can see the actual source code for index.php, the main page of my WordPress site, in a <textarea> element. Any changes I make to the file will be saved to disk, and the next time I view the front page of my blog, I’ll see them. Download from www.wowebook.com ptg If you know how to edit these files, you can customize WordPress to your heart’s con- tent. If you don’t want to make changes to your WordPress theme by hand, you can download and install themes that other people have created at http://wordpress.org/extend/themes/. You can download the themes and place them within your WordPress installation so that they can be applied to your weblog. You can also use those themes as starting points to create your own custom theme. The functionality of WordPress can also be extended using plug-ins. This is yet another advantage of running your own installation of WordPress. Not only can you create your own themes and install themes created by other people, but you can also extend WordPress using plug-ins that you download or you can write the new functionality yourself. A directory of available plug-ins can be found at http://wp-plug-ins.net/. This directory contains hundreds of plug-ins for WordPress. Installing plug-ins is straightforward. Let’s say I want to install Yet Another Related Posts plug-in, which automatically lists posts related to the post currently being viewed in WordPress. First, I go to the download site and download the plug-in. Here is the URL for the plug-in: http://wordpress.org/extend/plug-ins/yet-another-related-posts-plug-in/ After I’ve downloaded the file, I have to expand the archive and copy the plug-in direc- tory into the wp-content/plug-ins directory in the WordPress installation directory. At that point, I can click the Plug-ins tab inside WordPress and I should see that the Related Posts plug-in is installed, as shown in Figure 22.9. WordPress 673 22 FIGURE 22.9 The Related Posts entry on the WordPress Plug-ins page. After the plug-in is installed and activated using the Activate button on the Plug-in list, I can configure the options for the plug-in using the Related Posts Options tab that appears Download from www.wowebook.com ptg once the Related Posts plug-in is activated. Then all I have to do is go to my single-page archive post and find a spot for the related_posts() call to include the list of related posts. The biggest advantage of installing your own copy of WordPress is the vast number of themes and plug-ins that are available. If you want to use WordPress but you don’t want to deal with the overhead of setting it up, you can create your own WordPress blog at http://wordpress.com/. MediaWiki Many applications are available for publishing wikis. I’ve chosen to discuss MediaWiki because it’s written in PHP, so it can be installed at a wide range of web hosts, and because it is relatively simple to set up. MediaWiki is also widely adopted, and it’s the plumbing for Wikipedia, the most popular wiki. Because of its popularity, the software is undergoing constant improvement, and many extensions are available for the software. The main downside of publishing a site using MediaWiki is that it won’t give you a great opportunity to use or improve your HTML skills. Content in MediaWiki is entered using MediaWiki’s internal markup language. MediaWiki markup is translated into HTML tags, though, so even though you use different syntax, knowledge of how web pages are constructed will still help you lay out your pages using MediaWiki’s markup language. Here’s an example of MediaWiki markup: == Sample Heading == This is a paragraph. This is a paragraph containing ‘’’Bold text’’’. Here’s an [http://www.example.com outbound link]. And here’s the equivalent in HTML: <h2> Sample Heading </h2> <p>This is a paragraph.</p> <p>This is a paragraph containing <b>Bold text</b>.</p> <p>Here’s an <a href=”http://www.example.com”>outbound link</a>. The first thing you should notice is that unlike HTML, in MediaWiki markup, white- space counts. When you skip lines between paragraphs, MediaWiki converts those breaks into paragraph tags. Headings are specified using equals signs. Two equals signs are con- verted to <h2>, four are converted to <h4>, and so on. MediaWiki markup can also be 674 LESSON 22: Content Management Systems and Publishing Platforms Download from www.wowebook.com ptg used to apply inline tags as well as block-level tags. As you can see, I used ‘’’ to make some text bold, and I created an outbound link from the wiki. You can also use MediaWiki markup to create tables, include images in pages, and take on most of the other tasks that you can accomplish with HTML. There’s a guide to MediaWiki’s markup language at the following page: http://meta.wikimedia.org/wiki/Help:Editing This is a wiki page, and if you had some information to add to the discussion of wiki markup, you could add it. Downloading and Installing MediaWiki The download and installation process for MediaWiki is similar to the process for WordPress. To download the software, go to http://www.mediawiki.org/wiki/Download. Find the most recent release and download that archive. After you’ve expanded the archive, rename the folder, which probably has a name such as mediawiki-1.15.4. The name you give it will appear in the URL, so you probably want to pick mediawiki or just wiki. Upload or copy all the files into the document root of your server (or into the directory where you want the wiki to reside), and then go to the URL where you just uploaded the files. You’ll see a page like the one in Figure 22.10, which indicates that you need to go through the MediaWiki installation process. MediaWiki 675 22 When you click the Setup link, the MediaWiki install script checks to make sure your server is configured properly and has the software that you need for MediaWiki to work. It also asks you to answer a few questions. Some are easy, such as the name of the site and the email address for the person running the site. Others are not so easy, such as the caching configuration. You can safely choose No Caching for that one. If MediaWiki is able to write to your configuration files (based on the permissions on those files and the privileges that the web server runs with), it allows you to enter all FIGURE 22.10 MediaWiki needs to be installed. Download from www.wowebook.com . plug-in. Here is the URL for the plug-in: http://wordpress.org/extend/plug-ins/yet-another-related-posts-plug-in/ After I’ve downloaded the file, I have to expand the archive and copy the plug-in. plug-ins that you download or you can write the new functionality yourself. A directory of available plug-ins can be found at http://wp-plug-ins.net/. This directory contains hundreds of plug-ins. archive and copy the plug-in direc- tory into the wp-content/plug-ins directory in the WordPress installation directory. At that point, I can click the Plug-ins tab inside WordPress and I should