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G-WAN, output headers from a CGI script

I am trying to set the HTTP header as Content-Type by CGI script.

In PHP :

 header('Content-Type: text/plain'); // or echo 'Content-Type: text/plain', "\r\n\r\n"; // as first line

or in Go :

 fmt.Print("Content-Type: text/plain\r\n\r\n") // as first line

Both do not affect the output.

How can I do that?

EDIT

I also tried the following in Go using the CGI package:

 package main import "fmt" import "os" import "net/http/cgi" func main() { r,e := cgi.Request() if e != nil { fmt.Println(e) os.Exit(200) } fmt.Printf("%#v", r) os.Exit(200) }

but I get the error:

 cgi: failed to parse REQUEST_URI into a URL:
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1 answer

Question 1:

If your script returns a valid HTTP return code (e.g. 200 ), the G-WAN builds the appropriate HTTP headers if they no longer exist (starting with "HTTP/1.x 200 OK" here).

So, to force a given content-type using scripting languages ​​(except for those that support the G-WAN API, such as C, C ++, D and Objective-C), you need to return 1 and define ALL HTTP headers of your response .

Programming languages ​​that support the G-WAN API can use get_env(argv, REPLY_MIME_TYPE); (as shown in fractal.c and others), and the G-WAN will build the rest of the headers.

Question 2:

The REQUEST_URI environment variable (although useful) is not part of the supported CGI v1 specification (RFC-3875). I asked for REQUEST_URI be added in a future version.

G-WAN-supplied script examples list the supported variables on v3.12:

 // ---------------------------------------------------------------------------- // CGI/1.1 environment variables: // ---------------------------------------------------------------------------- // "AUTH_TYPE", // "" | "Basic" | "Digest" | etc. // "CONTENT_LENGTH", // "" | entity_length // "CONTENT_TYPE", // "" | content_type // "GATEWAY_INTERFACE", // "CGI/1.1" // "PATH_INFO", // "" | ( "/" path ) // "PATH_TRANSLATED", // disk filename for PATH_INFO // "QUERY_STRING", // "" | ?"hellox.c&name=toto" // "REMOTE_ADDR", // client IP address // "REMOTE_HOST", // client DNS name (or IP addr) // "REMOTE_IDENT", // client identity (RFC 1413), opt // "REMOTE_USER", // client identity (if auth) // "REQUEST_METHOD", // "GET" | "HEAD" | "PUT", etc. // "SCRIPT_NAME", // "" | ("/" path "hello.c") // "SERVER_NAME", // "gwan.com" | IP address // "SERVER_PORT", // "80" // "SERVER_PROTOCOL", // "HTTP/1.1" | "HTTP/1.0" | "HTTP/0.9" // "SERVER_SOFTWARE", // "G-WAN" // ----------------------------------------------------------------------------

Please note that you can access both the request and the parameters (if any) using the following (and faster) Go code:

 // args[1] /opt/gwan/10.10.20.80_80/#192.168.200.80/csp/hello.go // args[2] arg1=123 // args[3] arg2=456 for i := 1; i < len(os.Args); i++ { fmt.Printf("args[%d] %s<br>", i, os.Args[i]) }

UPDATE

We received this source code by email:

 package main import "fmt" import "os" func main() { p := "<h1>Hello world!</h1><p>This is dog bla</p>" fmt.Printf("%s 200 OK\r\n", os.Getenv("SERVER_PROTOCOL")) fmt.Print("Content-Type: text/html; charset=UTF-8\r\n") fmt.Print("Connection: Keep-Alive\r\n") fmt.Printf("Content-Length: %d\r\n",len(p)) fmt.Print("\r\n") fmt.Print(p) }

Please note that this code is incorrect: it does not even compile - and the G-WAN reports the following errors:

 loading. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Error: hell.go ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ # command-line-arguments 0.0.0.0_8080/#0.0.0.0/csp/hell.go:7: syntax error: unexpected semicolon or newline before { 0.0.0.0_8080/#0.0.0.0/csp/hell.go:9: non-declaration statement outside function body 0.0.0.0_8080/#0.0.0.0/csp/hell.go:10: non-declaration statement outside function body 0.0.0.0_8080/#0.0.0.0/csp/hell.go:11: non-declaration statement outside function body 0.0.0.0_8080/#0.0.0.0/csp/hell.go:12: non-declaration statement outside function body 0.0.0.0_8080/#0.0.0.0/csp/hell.go:13: non-declaration statement outside function body 0.0.0.0_8080/#0.0.0.0/csp/hell.go:14: non-declaration statement outside function body 0.0.0.0_8080/#0.0.0.0/csp/hell.go:16: syntax error: unexpected } 4|import "os" 5| 6|func main() 7!{ 8| p := "<h1>Hello world!</h1><p>This is dog bla</p>" 9| fmt.Printf("%s 200 OK\r\n", os.Getenv("SERVER_PROTOCOL")) 10| fmt.Print("Content-Type: text/html; charset=UTF-8\r\n") 11| fmt.Print("Connection: Keep-Alive\r\n") To run G-WAN, you must fix the error(s) or remove this Servlet.

Most likely, you did not notice that the program was “updated”: the old version, if any, was not replaced by a faulty version, updated when G-WAN started.

When you develop (edit scripts), you should always look at the terminal to check if your recently edited code is not compiling.

I recommend that you look at the (working) hello.go to find out what requirements are needed for the expected definition of main() and (crazy) return code .

If the return code is not used (for example, in your code), G-WAN will enter the default HTTP headers ( HTTP/0.9 200 OK in your case), which will bypass your HTTP headers (if any), and as a result Internet browser, wait until it expires, because it does not know the length of your response.

As indicated in the examples and in the manual, to tell the G-WAN not to create HTTP headers, you need to return a value in the range 1-99 ( 0 means close connection and 200-600 is reserved for HTTP return codes that tell the G-WAN to generate corresponding HTTP headers).

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