---
title: "Introduction to FastCGI"
subtitle: "Group 10"
author: "Andrew Fuller"
---

### In the beginning

One app, one web server

apache.c:
```
    if (page == "/loginform.html") {
        sendfile("templates/loginform.html");
    } else if (page == "/profile.html") {
        printf("Status: 200 OK\r\n");
        printf("Content-type: text/html\r\n");
        printf("\r\n");
        printf("<h1>Hello %s</h1>", user);
```


### CGI

Generate responses with an external process

Web server does:

```
$ export REQUEST_URI="/loginform.asp"
$ ./mycgi.exe
Status: 200 OK
Content-Type: text/html

<h1>Please login</h1>
<form action="/dologin">
...
```


### CGI

Requests are passed through envp and stdin

```
int main(int argc, char **argv, char **envp){
	int len = atoi(getenv("CONTENT_LENGTH"));
	char *req = malloc(len);

	read(STDIN_FILENO, len, req);

{'u','s','e','r','=','m','i','k','e','6','9','&'
 'p','a','s','s','=','t','h','r','i','l','l','7'}
```


### CGI

HTTP GET query string

```
char *query = getenv("QUERY_STR");
```


Which page was requested?

```
char *uri = getenv("REQUEST_URI");
```


HTTP POST vars? File uploads?

```
fread(buf, count, 1, stdin);
```


### CGI

Decouples web server from web app

No more embedded:

- mod_php
- mod_python
- mod_ruby
- mod_rack / phusion



### CGI

Spawn a new process for each request?

```
$ export REQUEST_URI="/loginform.asp"
$ ./mycgi.exe
$ export REQUEST_URI="/login.asp"
$ ./mycgi.exe
$ export REQUEST_URI="/profile.asp"
$ ./mycgi.exe
$ export REQUEST_URI="/deleteprofile.asp"
$ ./mycgi.exe
$ export REQUEST_URI="/redirect.asp"
$ ./mycgi.exe
```



### FastCGI

Advantages:

- Fast



### FastCGI

Fast:

```
$ ./myfcgi.exe
	Listening on 127.0.0.1:1337
```



### FastCGI

For each request, web server:

- Connects to fastcgi app
- Sends the request variables
- Reads the reply, forwards it to client



### FastCGI

```
127.0.0.1:1337
```

or

```
/tmp/myapp.sock
```

or

```
192.168.1.{90,91,92}:1337
```



### Terminal App

[Terminal](http://cmpt470.csil.sfu.ca:9010/terminal.html)



### Problems with FastCGI

![](photos/jerrychenme.png)



### Alternatives to FastCGI

SCGI - Simple Common Gateway Interface

WSGI - Web Server Gateway Interface

PSGI - Perl Server Gateway Interface

ISAPI - Internet Server Application Programming Interface



### SCGI

Simple



### SCGI

Simple protocol

New (2006)

Not widely used



### WSGI

Web Server Gateway Interface

Made for Python

They don't care about everyone else



### PSGI

Perl Server Gateway Interface

Made for Perl

They don't care about everyone else



### ISAPI

Internet Server API

Made by Microsoft

They don't care about everyone else

Uses DLLs and OS services, much tighter coupling



### FastCGI Support

Every major webserver can forward requests over FastCGI

Every major language can respond to FastCGI requests



### Q&A

Any questions?