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STM32 ETHERNET #6.2 HTTP WEBSERVER PART 3 || CGI (Common gateway Interface)
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Nov 20, 2021
Purchase the Products shown in this video from :: https://controllerstech.store ________________________________________________________________________________________ ETHERNET PART6.1 :::: https://youtu.be/m0iQo7ls9XE ETHERNET PART7 :::: https://youtu.be/6olMulM5SCg STM32 ETHERNET Playlist:: https://www.youtube.com/playlist?list=PLfIJKC1ud8ggZKVtytWAlOS63vifF5iJC STM32 Playlist :::: https://www.youtube.com/playlist?list=PLfIJKC1ud8gga7xeUUJ-bRUbeChfTOOBd DOWNLOAD THIS PROJECT FROM :::: https://controllerstech.com/stm32-ethernet-6-2-http-webserver-cgi/ _________________________________________________________________________________________ ******* SUPPORT US BY DONATING****** https://paypal.me/controllertech *******Join the Membership******* https://www.youtube.com/channel/UCkdqtSMnhYuMsJkyHOxiPZQ/join
View Video Transcript
0:01
[Music]
0:09
hello and welcome to controllers tech
0:13
this is another video in the ethernet
0:15
series and this is going to be the last
0:17
video on the raw apis
0:20
after this we will look into the
0:22
ethernet with the rtos
0:24
this video is the continuation from the
0:27
previous one where we sent the data to
0:29
the web server using the ssi
0:32
in this video we will see how to receive
0:35
data from the web server using the cgi
0:38
common gateway interface
0:41
as i mentioned this is the continuation
0:43
from the previous video i will also
0:45
continue where we left off last time
0:48
this here is the project
0:51
and this is how the web server looks
0:54
the ssi page updates every one second
0:57
and we display the values from the
0:59
controller
1:00
since we are sending the data from the
1:02
web server to the controller we need to
1:05
create a new web page
1:08
and for this purpose i am going to use
1:11
the html form
1:20
this looks good enough
1:22
let me change the heading real quick
1:30
it is here is the action which will act
1:32
after the submit button is clicked
1:35
let's keep it unchanged for now
1:40
the f name and l name are the parameters
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let me show you
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here f name is the first parameter and
1:51
john is the first value
1:54
similarly l name is the second parameter
1:57
and do is the second value
2:00
we will talk about these later
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the action for the form i wanted to call
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form dot
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cgi
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i will declare this later in the code
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let's copy this and we will create a
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html file
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i am calling it cgi form dot html
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this works fine
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you can see the action then the
2:52
parameters and their values
2:55
all right we will come back to this but
2:57
first we need to enable the cgi and to
3:00
do that we will go to the cube mx
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go to l w i p http advance parameters
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and enable the cgi hold style
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that's it click save to generate the
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project
3:30
if we build it we will get our usual
3:32
error about the custom fs data file
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you need to disable the use of custom fs
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data again
3:47
the next error will be about the fs data
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file
3:55
let's go to the http folder
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copy the html file here in the fs folder
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generate the fsdata.c file again
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now all the errors should be gone
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all right we are good to go
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i am going to write the functions in the
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same file that we use for the ssi
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last time we used the function set ssi
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handler to assign the ssi handler to the
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tags
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we are going to use a similar function
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for the cgi handler also
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here is the set cgi handler function and
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it takes 2 parameters
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the first is the pointer to a-t-c-g-i
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structure and second is the number of
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cgi handlers we are using
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this t-c-g-i structure is defined right
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above and it have two elements the file
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name of the cgi and the handler itself
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this is the function for the cgi handler
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let's copy this into our file
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i am calling it c g i form handler
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the c g i handler takes 3 parameters
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the first parameter i index provides the
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index of the cgi in the cgi array
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for example if you are using more than
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one cgi handlers this parameter will
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give the index of the handler being
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called
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the next is the num parameter and it
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gives the index of the parameter within
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the same handler
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for example in this tutorial i have used
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the f name and l name so this num
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parameter will basically indicate
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whether it's the f name parameter or the
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lname parameter that called the handler
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then comes the pc parameter and pc value
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they basically are the parameter and its
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value
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for example here in this case they will
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be f name and john or l name and do
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one last thing about this handler is
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that it should return the pointer to the
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html page basically the cgi page
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let's write the rest of the code now
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first of all we will define a structure
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with the file name and the handler
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i am calling it form cgi
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the file name will be same as we
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declared in the action of the html file
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and handler is the cgi handler
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now we will write the c g i handler
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since we are only using one handler the
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i index will be zero
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we have to write ay for loop for the
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number of parameters we have in our html
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file
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as i mentioned we have 2 parameters f
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name and l name
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if the f name parameter is detected we
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will copy the value into our name array
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and similarly if the parameters is l
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name we will concatenate the value to
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our initial string
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this way we will get the name as first
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name space last name
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at the end of this handler we need to
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return the pointer to the html file
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this is the name of the cgi file that we
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have created
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now we will set the cgi handlers
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the first parameter is the pointer to
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the tcgi structure
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we will pass the address of the form cgi
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here
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and the number of handlers are 1 in our
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case
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that's it since we are already calling
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the http server in it in our main file
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we don't need to do anything else
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let's build and test the code
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i have added the name in the live
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expression
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let's run it
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now we will go to the cgi form dot html
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type in the first and last name
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and click submit
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you can see the name has been stored in
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the array
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let's try something else
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the data did get stored but we have the
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leftover from previous data
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we need to clean the buffer before
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storing the new data
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before copying the first name we will
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clear the buffer
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let's test it now
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this time we got the data and there is
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no leftover from the last time
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we can still access the s s i page from
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the previous tutorial
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it keeps refreshing in the background
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in the meanwhile we can transfer data
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from the web server to our buffer
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now let's say you want to use another
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section for the data
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for example some buttons to control the
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leds
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to do that we will create another cgi
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handler
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i am calling it cgi led handler
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we will create another tcgi structure
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we need to change the handler also
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let's create an array of the cgi
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structures
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before setting the cgi handler we need
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to assign the tcgi structures to the
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array
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and now we will pass the structure array
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to the set handler function
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also we are using 2 handlers now
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finally we will write the cgi led
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handler
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since the l-e-d handler is the second
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element in the array the i index will be
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1.
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after this you do the rest of the
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processing in the similar way
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first check for the parameter and then
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check for the value
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based on that control the leds
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this is it for the video
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i hope you understood the usage of cgi
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in the http web server
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this is the last video using the raw api
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and the next video on the ethernet will
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use the rtos
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i will just cover the basic
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initialization using the rtos and the
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netcon
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that's it for today
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you can download the code from the link
13:32
in the description
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leave comments in case of any doubt
13:37
keep watching and have a nice day ahead
13:42
[Music]
13:55
you
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