Including and Opening files

If you've taken our basic PHP course or 0:00 really done almost anything in PHP, you've already been reading files. 0:03 They include and require statements read additional files into the current file. 0:08 This is a great way to cut back and rewriting the same thing all the time. 0:13 We can write things once and include them wherever we want. 0:18 But this course is really about giving you control. 0:22 We want to be able to do something with those files, 0:25 besides just dumping them into the current file. 0:28 So, let's take a look at some of the other options we have for reading files. 0:31 We're going to create a form, and bring in country, and 0:36 state drop-downs from some other files. 0:39 If we click on the HTML countries.html, and view the page source. 0:41 You can see that this is a list of drop down options. 0:48 The other HTML files are formatted the same way, and 0:51 you can browse each of them if you'd like. 0:54 Back in work spaces create a new file name state_formed.php. 1:00 Let's add our form tag and then create a country drop down. 1:09 <label for="country">Country</label> And then, our select. 1:20 For country, we're just going to include our countries file. 1:44 Let's view this in the browser. 1:59 We can see that their drop down is populated. 2:11 Let's go back and add a state drop down now using a little more control this time. 2:13 We'll add a label for our state. 2:23 And then our select. 2:31 This time we'll start by reading the file with the fopen function. 2:47 This function opens a connection to a file, 2:53 and returns a file handler that we can use to connect to the file. 2:55 This is the same kind of thing that we do when we set up a connection to a database. 3:00 To open a connection, we first tell it, which file we want to open, and 3:04 then tell it which mode we want to use. 3:08 What are we doing with the file? 3:11 Reading? 3:13 Writing? 3:13 Appending? 3:14 Or even creating a file if it doesn’t exist. 3:15 Check the notes associated with this video for mode options, and 3:18 additional features of fopen. 3:22 First we pass data/ html/states.html. 3:24 And then, since we want to read the file, we use r as the mode. 3:31 We'll wrap this in an F statement, so 3:36 we can perform our actions only if we're actually able to open the file. 3:38 We set our file handle equal to the fopen And now, we perform our actions. 3:47 The first action I want to add within the statement is the action to close the file. 3:56 Use fclose and pass the file handler, Before I close the file. 4:01 I want to loop over each line, we can create any kind of loop we want. 4:09 We could loop through only a specific number of lines, or 4:14 until we find a certain character. 4:18 I want to loop through all the lines in this file. 4:20 So, I will use the end of file function. 4:23 While not file, and a file, and our file handler. 4:27 To read each line, we use that fgets function. 4:38 This returns the current line as a string, and moves the pointer to the next line. 4:43 We can now echo that line. 4:51 Let's preview this in the browser again. 4:56 This time we see the state drop down as well. 5:00 But we haven't actually done anything more than include the file. 5:04 So, let's say, that I want to default the selection to Oregon. 5:07 Let's go back to Workspaces, and add some additional code. 5:11 If the string position 5:20 of line for Oregon. 5:25 This will check if my line contains the string Oregon. 5:34 If so, then I want to string replace. 5:38 Oregon, with 5:43 selected Oregon. 5:48 Else, we'll echo the line. 6:06 Let's check our browser again. 6:10 This time Oregon is selected by default. 6:14 We could make any comparisons, or manipulations we wanted to this line. 6:17 But let's check out another function for reading files. 6:21