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Ada Programming/Libraries/Web/AWS
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Libraries Web AWS
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AWS, the Ada Web Server, is a complete framework to develop Web based applications. The main part of AWS is the embedded web server. This small, yet powerful, Web server can be embedded into your application, so it will be able to talk with a standard Web browser. Around this Web server, a lot of services have been developed.
AWS supports SOAP Web Services and the REST architecture.
Sample code
Hello World
The famous Hello World demo for AWS, a complete Web server that will display "Hello world!" for every request made to localhost on port 8080.
with AWS.Default;
with AWS.Response;
with AWS.Server;
with AWS.Status;
procedure Hello_World is
WS : AWS.Server.HTTP;
function HW_CB (Request : AWS.Status.Data) return AWS.Response.Data is
begin
return AWS.Response.Build ("text/html", "Hello world !");
end HW_CB;
begin
AWS.Server.Start (WS, "Hello World", Callback => HW_CB'Access);
delay 60.0;
AWS.Server.Shutdown (WS);
end Hello_World;
Setting server configuration and waiting for an event
It is possible to pass configuration parameters for the server using a record. It is also possible to use a built-in procedure on AWS to wait for an event.
callbacks.adb
package body Callbacks is
function HW_CB (Request : AWS.Status.Data) return AWS.Response.Data is
begin
return AWS.Response.Build ("text/html", "Hello world !");
end HW_CB;
end Callbacks;
callbacks.ads
with AWS.Status;
with AWS.Response;
package Callbacks is
function HW_CB (Request : AWS.Status.Data) return AWS.Response.Data;
end Callbacks;
main.adb
with AWS.Config.Set;
with AWS.Server;
procedure Main is
use AWS;
Host : constant String := localhost;
Port : constant := 8080;
Web_Server : Server.HTTP;
Web_Config : Config.Object;
begin
Setup
Config.Set.Server_Host (Web_Config, Host);
Config.Set.Server_Port (Web_Config, Port);
Start the server
Server.Start (Web_Server => Web_Server,
Callback => Callbacks.HW_CB'Access,
Config => Web_Config);
Wait for the Q key
Server.Wait (Server.Q_Key_Pressed);
Stop the server
Server.Shutdown (Web_Server);
end Main;
REST
Interface with bitcoind JSON-RPC.
bitcoin.adb
with AWS.Client;
with AWS.Headers;
with AWS.Headers.Set;
with AWS.Response;
package body Bitcoin is
function Get_Wallet_Info return AWS.Response.Data is
hdrs : AWS.Headers.List := AWS.Headers.Empty_List;
begin
AWS.Headers.Set.Add(hdrs, Content-Type, text/plain);
return AWS.Client.Post(URL => http://127.0.0.1:8332/,
Data => {""jsonrpc"": ""1.0"", ""id"":""test"", ""method"": ""getwalletinfo"", ""params"": []},
User => bitcoinrpcUSERNAME,
Pwd => bitcoinrpcPASSWORD,
Headers => hdrs);
end Get_Wallet_Info;
end Bitcoin;
Create the bitcoin.conf file by opening Bitcoin Core and clicking on the corresponding button on the options window. The following is an example configuration file. Then reopen bitcoin-qt or start the bitcoind daemon to start the server. The bitcoin-cli program and the testnet network can be used for testing RPC commands.
bitcoin.conf
# Expose the RPC/JSON API
server=1
rpcuser=USERNAME
rpcpassword=PASSWORD
See also
Wikipedia
Web application
Web services
SOAP
Wikibook
Ada Programming
Ada Programming/Libraries (Other Language Libraries)
External links
adacore aws
AWS live documentation
Web-enabling Ada Applications with AWS, presentation by J-P. Rosen