Index

Overview

The URLAPI is a standardized application program interface (API) for accessing the NCBI $QBl_{A}st$ system. It uses direct HTTP-encoded requests to NCBI web server.

These encoded requests should be directed to the NCBI cgi-bin program:

http://www.ncbi.nlm.nih.gov/blast/Blast.cgi

A few of the highlighted features and advantages of using HTTP requests for the service are:

• no program should be downloaded from NCBI ftp site to use NCBI BLAST service,
• easy to keep backward compatibility of API,
• no need to transfer sequences from NCBI to local machines,
• no need to hack Web NCBI BLAST programs to run scripts,

Any HTTP browser or application capable to make HTTP requests can be utilized to use URLAPI. There are many tools around which can be used to make HTTP requests, for example - PERL modules, C libraries, lynx program, etc. Almost all examples in this document use 'lynx' browser by default, but 'netscape' and IE can be used for the same purposes.

Basically, in order to issue an URLAPI command your program will need to:

1. Make a connection to port 80 to NCBI web server (in UNIX: telnet www.ncbi.nlm.nih.gov 80)

2. Send the following commands to the port:

       POST /blast/Blast.cgi HTTP/1.0
       User-Agent: Hi_there
       Connection: Keep-Alive
       Content-type: application/x-www-form-urlencoded
       Content-Length: 200
         
       CMD=Put&QUERY=555... etc