PHP-and-MySQL/C2/Common-Errors-Part-3/English-timed
From Script | Spoken-Tutorial
Time | Narration |
---|---|
0:00 | Right now I am onto the last two common errors that I have included. |
0:05 | And we will start with the hard one. |
0:09 | This is php header and we are using "header" function going to a location. |
0:14 | And here I have got some html code. |
0:18 | This is a header tag, I am saying "Welcome!". |
0:21 | And our "goto" variable is "google dot com". |
0:26 | If the "goto" exists, which it currently does, we are going to redirect the page to a u-r-l "google dot com". |
0:35 | Right now, this will return an error. |
0:37 | And the error is - Oh! um... Okay that’s why. "o b start". |
0:50 | Lets get rid of this. That wasn’t supposed to be there. That code is to fix the error! |
0:56 | Sorry, so we will go to "php header" and we have got "Welcome!" - our html code. |
1:03 | Then a warning - "Cannot modify header information – headers already sent by..." and all of this. |
1:10 | Okay so our headers have already been sent. This is the line no. by the way. |
1:16 | 1, 2, 3 so if it gives you an error like "phpheader dot php" colon 3, then the error has occurred on the line no. 3. |
1:26 | So that's where the error is - on line 3, okay? |
1:32 | And this error has been generated by line 9, which if you go here, is our "header" function. |
1:39 | So the reason that this is happening is we are already sending our html code. |
1:47 | If I get rid of this by commenting it, and I were to refresh then we would be redirected to google. |
1:54 | But the point is that we want this welcome header here. |
1:59 | And you can’t actually put html before a header function, going to location and other features of this function. |
2:10 | You shouldn't do so. |
2:15 | So as you saw a minute ago that is "ob underscore start". |
2:20 | What this does is, it fixes this problem for us. |
2:25 | So I can come here to "phpheader" and it works, even though I have still got my html code echoed here before my header. |
2:37 | So without this we get an error (pause) and with this our header works fine, okay? |
2:47 | Despite the initial rule of no html output before header up here. |
2:53 | That should be pretty clear by now. |
2:55 | Now, the last one is extremely simple. |
2:58 | I don’t even need to explain it but anyway. |
3:02 | This is "include a file which doesn’t even exist" named as "idontexist dot php". |
3:08 | So lets have a look. Um.. where is it? "missing dot php". |
3:13 | Oh no! Its not. "open dot php". |
3:16 | Okay! So - include "idontexist dot php" failed to open stream; no such file or directory in that name here. |
3:25 | Our file name and directory on line 3. |
3:27 | So lets come to line 3. |
3:30 | And that is the only line of significant code in this file. |
3:35 | We have another warning here - Failed to open "idontexist dot php" for inclusion and all of this. So we get two errors. |
3:43 | This is quite messy when you have a page that has "include a header file". |
3:50 | Then these don’t look too nice. I mean you have probably been in a website before and you have seen this at the top. |
3:57 | You need to be attractive. So you can put a "@ (at)" symbol in front and refresh. |
4:02 | That won't show the error anymore. |
4:06 | But it doesn’t excuse the fact that the file doesn’t exist. |
4:10 | So the content of the file which doesn’t exist, won’t be included. |
4:14 | But yes, to be honest, looking at this, this is really pretty much self explanatory. I just thought I should explain this anyways. |
4:23 | So we have got a small collection of errors that you might come across when you are programming in php. |
4:30 | If there are other errors that you are getting, then please message me and I will be happy to help. |
4:39 | Please subscribe for latest updates. Thanks for watching. This is Evan Varkey dubbing for the Spoken Tutorial project. |