Document how to build the Windows GUI version (headless). Document API functions implemented in Cmd.

API.go

@@ -60,10 +60,10 @@ func parseDuration(input string) (result time.Duration) {
 }
 
 /*
-apiConsole provides a websocket to send/receive internal commands
+apiConsole provides a websocket to send/receive internal commands.
 
 Request:    GET /console
-Result:     200 with JSON structure apiResponsePeerSelf
+Result:     Upgrade to websocket. The websocket message are texts to read/write.
 */
 func apiConsole(w http.ResponseWriter, r *http.Request) {
 	c, err := webapi.WSUpgrader.Upgrade(w, r, nil)

README.md

@@ -18,6 +18,15 @@ To reduce the binary size provide the linker switch -s which will "Omit the symb
 go build -ldflags "-s"
 ```
 
+### Windows Headless Version
+
+To build a headless version (like a typical Windows GUI application) that does not show the command line window use the following linker switch. The second example reduces the file size.
+
+```
+go build -ldflags "-H=windowsgui"
+go build -ldflags "-H=windowsgui -s"
+```
+
 ## Use
 
 The config filename is hard-coded to `Config.yaml` and is created on the first run. Please see the core library for individual settings to change.
@@ -77,6 +86,53 @@ APITimeoutRead:     "10m"               # The maximum duration for reading the e
 APITimeoutWrite:    "10m"               # The maximum duration before timing out writes of the response. This includes processing time and is therefore the max time any HTTP function may take.
 ```
 
+## API Functions
+
+All API functions provided by the core library are described [here](https://github.com/PeernetOfficial/core/tree/master/webapi).
+
+In addition, this application also provides these functions:
+
+```
+/console                        Websocket to send/receive internal commands
+/shutdown                       Graceful shutdown
+```
+
+### Console
+
+This provides a websocket to send/receive internal commands in the same way provided via the command line interface. The websocket messages sent to the API are the input texts from the end-user, and the messages received from the API are the text outputs.
+
+This can be useful as internal debug interface in clients.
+
+```
+Request:    GET /console
+Result:     Upgrade to websocket. The websocket message are texts to read/write.
+```
+
+### Shutdown
+
+This gracefully shuts down the application. Actions: 0 = Shutdown.
+
+```
+Request:    GET /shutdown?action=[action]
+Result:     200 with JSON structure apiShutdownStatus
+```
+
+```go
+type apiShutdownStatus struct {
+	Status int `json:"status"` // Status of the API call. 0 = Success.
+}
+```
+
+Example request: `http://127.0.0.1:112/shutdown?action=0`
+
+Example response:
+
+```json
+{
+    "status": 0
+}
+```
+
 ## Error Handling
 
 The application exits in case of the errors listed below and uses the specified exit code. Applications that launch this application can monitor for those exit codes. End users should look into the log file for additional information in case any of these errors occur, although some of them are pre log file initialization.