millis() in http get requset

Please help me, this is my code. I want to replace delay() because its blocking arduino to do others things.

i already replace it by millis() but not work. if someone have solution?

void server_request ()
{

Serial.println("HTTP get method :");
Serial.print("AT\r\n");
SIM900.println("AT"); /* Check Communication */
delay(5000);

Serial.println("AT+SAPBR=3,1,"CONTYPE",""");
SIM900.println("AT+SAPBR=3,1,"CONTYPE","""); /* Connection type GPRS */
delay(5000);

SIM900.println("AT+SAPBR=3,1,"APN","www.apn.com""); /* APN of the provider */
delay(5000);

SIM900.println("AT+SAPBR=1,1"); /* Open GPRS context */
delay(5000);

SIM900.println("AT+SAPBR=2,1"); /* Query the GPRS context */
delay(5000);

SIM900.println("AT+HTTPINIT"); /* Initialize HTTP service */
delay(5000);

SIM900.println("AT+HTTPPARA="CID",1"); /* Set parameters for HTTP session */
delay(5000);

SIM900.println("AT+HTTPPARA="URL","domain-name.com:3000/data?variable1=value1&variable2=value2""); /* Set parameters for HTTP session */
delay(5000);

SIM900.println("AT+HTTPACTION=0"); /* Start GET session */
delay(5000);

//SIM900.println("AT+HTTPREAD"); /* Read data from HTTP server */
//delay(5000);

SIM900.println("AT+HTTPTERM"); /* Terminate HTTP service */
delay(5000);

Serial.println("insertion done");
SIM900.println("AT+SAPBR=0,1"); /* Close GPRS context */
//delay(5000);
}

NB : i put this void in the loop.
please i need your help, because i cant found solution for this problem.
thanks

It is not possible to replace delay() with millis(), you have to rewrite your sketch.

Start with the Blink Without Delay.
Use that for a millis timer of 5 seconds.
Use a counter/index and increment that (every 5 seconds).

One way to do this, is to put all the SIM900 strings in a table, and go through that table in the millis timer.
Which Arduino board are you using ? Perhaps the table can be in PROGMEM.

The demo Several Things at a Time is an extended example of BWoD and illustrates the use of millis() to manage timing without blocking. It may help with understanding the technique.

Have a look at Using millis() for timing. A beginners guide if you need more explanation.

...R