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--- http_get_custom [2021/07/13 11:10] – emozolyak
+++ http_get_custom [2023/03/28 10:49] (current) – atolstov
@@ Line 1: / Line 1: @@
 ====== HTTP request implemention using custom protocol ======
 The following example sends a HTTP string template to the TCP port upon the register change in the custom protocol.
-Once the response comes, is is copied in the 'response' global variable which is returned to the system with the **readRegister** function.
+Once the response comes, is is copied in the //response// global variable which is returned to the system with the **readRegister** function.
 <code lua>
@@ Line 11: / Line 11: @@
 Accept: application/json
 Content-Type: application/json
 ]]
 response = "no data"
@@ Line 29: / Line 28: @@
 function writeRegister (reg, device, unitId, newValue)
-   sendString(get_example)
+   sendString(get_example .. "\n")
    local s = read_string()
@@ Line 56: / Line 55: @@
     return response
 end
+</code>
+===== How to change request parameters  =====
+When you want to dynamically change your request paramters, the above example could be further extended to this verstion:
+<code lua>
+GET_TEMPLATE = { getPath = "GET /api/registers/" ,
+                 reg = 611,  -- can be modified from outside
+                 getTail =  " HTTP/1.1" .. "\r\n",
+                 acceptHeader = "Accept: application/json".."\r\n",
+                --  host = "Host: 192.168.1.110".."\r\n",
+                 host = "Host: 127.0.0.1".."\r\n",
+                 apiKey = "X-WH-APIKEY: 4025D32205ADC52E8604690FFADFB4600B8D41AA".."\r\n",
+                 endLine = "\r\n"
+}
+function GET_TEMPLATE : make()
+    local newRequest =   self.getPath
+                      .. self.reg
+                      .. self.getTail
+                      .. self.acceptHeader
+                      .. self.host
+                      .. self.apiKey
+                      .. self.endLine
+    return newRequest
+end
+function createDevices ()
+    addDevice{name = "CMD",  shift = 0, base = 10, xtraFields = {} };
+end
+function readRegister (reg, device, unitId)
+  return status_
+end
+function writeRegister (reg, device, unitId, newValue)
+    -- check for zero
+    if (newValue == 0) then
+        status_ = false
+        return true              -- no GET will be done
+    else
+        GET_TEMPLATE.reg = newValue -- change target  for request
+    end
+    sendString_(GET_TEMPLATE : make() )
+    local response_ = readAll()
+    if (#response_ > 0) then
+        DEBUG("got something ... " .. response_)
+        status_ = 1
+    else
+        status_ = false
+    end
+    return true
+end
+------------------ Helpers ---------------
+-- new sendString version
+function sendString_(s)
+                                                DEBUG("Going to send: " .. s)
+    local sendBuf = {}
+    for i = 1, #s do
+        table.insert(sendBuf, s : byte(i) )
+    end
+    sendBytes(sendBuf)
+end
+-- read everything that is in buffer
+function readAll()
+    local rbuf = {}
+    repeat
+            local b = readString(1)
+            if b then
+                table.insert(rbuf, b)
+            end
+    until (not b)
+    return table.concat(rbuf)
+end
+------------ Not in use ------------------
+function onScanStart ()
+end
 </code>