PHP-and-MySQL/C2/Common-Errors-Part-3/English-timed
From Script | Spoken-Tutorial
| Time | Narration |
| 00:00 | Right now I am onto the last two common errors that I have included. |
| 00:05 | And we will start with the hard one. |
| 00:09 | This is the php header and we are using "header" function going to a location. |
| 00:14 | And here, I have got some html code. |
| 00:18 | This is a header tag, I am saying "Welcome!". |
| 00:21 | And our $goto variable is "google dot com". |
| 00:26 | If the $goto exists which it currently does, we are going to redirect the page to a u-r-l "google dot com". |
| 00:35 | Right now, this will return an error |
| 00:37 | and the error is - Oh! um... Okay that’s why. "o b_ start()". |
| 00:50 | Let's get rid of this. That wasn’t supposed to be there. That code is to fix the error! |
| 00:56 | Sorry, so we will go to the "php header" and we have got "Welcome!" - our html code. |
| 01:03 | Then a Warning - "Cannot modify header information – headers already sent by..." and all of this. |
| 01:10 | Okay; so our headers have already been sent. This is the line number, by the way. |
| 01:16 | 1, 2, 3 so if it gives you an error like "phpheader dot php" colon 3 then the error has occurred on the line number 3. |
| 01:26 | So that's where the error is - on line 3, okay? |
| 01:32 | And this error has been generated by line 9 which if you go here, is our "header" function. |
| 01:39 | So, the reason that this is happening is we are already sending our html code. |
| 01:47 | If I get rid of this by commenting it and I were to refresh then we would be redirected to google. |
| 01:54 | But the point is that we want this "Welcome" header here. |
| 01:59 | And you can’t actually put html before a header function, going to Location and other features of this function. |
| 02:10 | You shouldn't do so. |
| 02:15 | So, as you saw a minute ago, that is "ob underscore start()". |
| 02:20 | What this does is, it fixes this problem for us. |
| 02:25 | So, if I come here to "phpheader" and it works even though I have still got my html code echoed here, before my header. |
| 02:37 | So, without this we get an error (pause) and with this our header works fine, okay? |
| 02:47 | Despite the initial rule of 'no html output before header', up here. |
| 02:53 | That should be pretty clear by now. |
| 02:55 | Now, the last one is extremely simple. |
| 02:58 | I don’t even need to explain it but anyway. |
| 03:02 | This is include a file which doesn’t even exist named as "idontexist dot php". |
| 03:08 | So, let's have a look. Um.. where is it? "missing dot php". |
| 03:13 | Oh no! It's not. "open dot php". |
| 03:16 | Okay! So - include idontexist dot php failed to open stream: No such file or directory in that name here. |
| 03:25 | Our file name and directory on line 3. |
| 03:27 | So, let's come to line 3. |
| 03:30 | And that is the only line of significant code in this file. |
| 03:35 | We have another warning here - Failed to open "idontexist dot php" for inclusion... and all of this. So, we get two errors. |
| 03:43 | This is quite messy when you have a page that has include a header file. |
| 03:50 | Then these don’t look too nice. I mean you have probably been in a website before and you have seen this is at the top. |
| 03:57 | You need to be attractive. So, you can put a "@ (at)" symbol in front of it. refresh. |
| 04:02 | That won't show the error anymore. |
| 04:06 | But, it doesn’t excuse the fact that the file doesn’t exist. |
| 04:10 | So the content of the file which doesn’t exist, won’t be included. |
| 04:14 | But yes, to be honest, looking at this, this is really pretty much self explanatory. I just thought I should explain this anyway. |
| 04:23 | So, we have got a small collection of errors that you might come across when you are programming in php. |
| 04:30 | If there are other errors that you are getting, then please message me and I will be happy to help. |
| 04:39 | Please subscribe for latest updates. Thanks for watching. This is Evan Varkey, dubbing for the Spoken Tutorial project. |
