API extract individual attributes - #462

CHANGELOG_LATEST.md

@@ -37,6 +37,7 @@
 - Junkers ISM2 and IPM in warm water mode [#437](https://github.com/emsesp/EMS-ESP32/issues/437)
 - Added Shower Alert trigger time and cold shot time [#436](https://github.com/emsesp/EMS-ESP32/issues/436)
 - Improved Table layout in Web UI (searching, filtering, sorting, exporting to CSV)
+- API fetch individual attributes from an entity [#462](https://github.com/emsesp/EMS-ESP32/issues/462)
 
 ### Fixed
 

src/command.cpp

@@ -86,7 +86,7 @@ uint8_t Command::process(const char * path, const bool is_admin, const JsonObjec
         return message(CommandRet::ERROR, "unknown device", output);
     }
 
-    // the next value on the path should be the command
+    // the next value on the path should be the command or entity name
     const char * command_p = nullptr;
     if (num_paths == 2) {
         command_p = p.paths()[1].c_str();
@@ -104,7 +104,7 @@ uint8_t Command::process(const char * path, const bool is_admin, const JsonObjec
         }
     }
 
-    // some commands may be prefixed with hc. or wwc. so extract these if they exist
+    // some commands may be prefixed with hc. wwc. or hc/ or wwc/ so extract these if they exist
     // parse_command_string returns the extracted command
     command_p = parse_command_string(command_p, id_n);
     if (command_p == nullptr) {
@@ -189,7 +189,7 @@ const char * Command::parse_command_string(const char * command, int8_t & id) {
     }
 
     // make a copy of the string command for parsing
-    char command_s[100];
+    char command_s[30];
     strlcpy(command_s, command, sizeof(command_s));
 
     // look for a delimeter and split the string
@@ -202,7 +202,7 @@ const char * Command::parse_command_string(const char * command, int8_t & id) {
             p      = command_s; // reset and look for _
             breakp = strchr(p, '_');
             if (!breakp) {
-                return command;
+                return command; // no delimeter found, return the whole string
             }
         }
     }
@@ -214,10 +214,8 @@ const char * Command::parse_command_string(const char * command, int8_t & id) {
     } else if (!strncmp(command, "wwc", 3) && start_pos == 5) {
         id = command[start_pos - 2] - '0' + 8; // wwc1 has id 9
     } else {
-#if defined(EMSESP_DEBUG)
+        id = 0; // special case for extracting the attributes
-        LOG_DEBUG(F("[DEBUG] Command parse error, unknown hc/wwc in %s"), command_s);
+        return command;
-#endif
-        return nullptr;
     }
 
     return (command + start_pos);
@@ -244,13 +242,12 @@ uint8_t Command::call(const uint8_t device_type, const char * cmd, const char *
     // see if there is a command registered
     auto cf = find_command(device_type, cmd);
 
-    // check if its a call to and end-point to a device, i.e. has no value
+    // check if its a call to and end-point to a device
     // except for system commands as this is a special device without any queryable entities (device values)
-    // exclude SYSTEM
     if ((device_type > EMSdevice::DeviceType::SYSTEM) && (!value || !strlen(value))) {
         if (!cf || !cf->cmdfunction_json_) {
 #if defined(EMSESP_DEBUG)
-            LOG_DEBUG(F("[DEBUG] Calling %s command '%s' to retrieve values"), dname.c_str(), cmd);
+            LOG_DEBUG(F("[DEBUG] Calling %s command '%s' to retrieve attributes"), dname.c_str(), cmd);
 #endif
             return EMSESP::get_device_value_info(output, cmd, id, device_type) ? CommandRet::OK : CommandRet::ERROR; // entity = cmd
         }

src/emsdevice.cpp

@@ -915,13 +915,26 @@ bool EMSdevice::get_value_info(JsonObject & output, const char * cmd, const int8
         tag = DeviceValueTAG::TAG_HC1 + id - 1;
     } else if (id >= 9 && id <= 19) {
         tag = DeviceValueTAG::TAG_WWC1 + id - 9;
-    } else if (id != -1) {
+    }
-        return false; // error
+
+    // make a copy of the string command for parsing
+    char command_s[30];
+    strlcpy(command_s, cmd, sizeof(command_s));
+    char * attribute_s = command_s;
+
+    // if id=0 then we have a specific attribute to fetch instead of the complete record
+    if (id == 0) {
+        char * p      = command_s;
+        char * breakp = strchr(p, '/');
+        if (breakp) {
+            *breakp     = '\0';
+            attribute_s = breakp + 1;
+        }
     }
 
     // search device value with this tag
     for (auto & dv : devicevalues_) {
-        if (strcmp(cmd, Helpers::toLower(read_flash_string(dv.short_name)).c_str()) == 0 && (tag <= 0 || tag == dv.tag)) {
+        if (strcmp(command_s, Helpers::toLower(read_flash_string(dv.short_name)).c_str()) == 0 && (tag <= 0 || tag == dv.tag)) {
             int8_t  divider    = (dv.options_size == 1) ? Helpers::atoint(read_flash_string(dv.options[0]).c_str()) : 0;
             uint8_t fahrenheit = !EMSESP::system_.fahrenheit() ? 0 : (dv.uom == DeviceValueUOM::DEGREES) ? 2 : (dv.uom == DeviceValueUOM::DEGREES_R) ? 1 : 0;
 
@@ -1060,6 +1073,25 @@ bool EMSdevice::get_value_info(JsonObject & output, const char * cmd, const int8
                 json[value] = "not set";
             }
 
+            // if id is 0 then we're filtering on an attribute, go find it
+            if (id == 0) {
+#if defined(EMSESP_DEBUG)
+                EMSESP::logger().debug(F("[DEBUG] Attribute '%s'"), attribute_s);
+#endif
+                if (json.containsKey(attribute_s)) {
+                    JsonVariant data = json[attribute_s];
+                    output.clear();
+                    output["api_data"] = data;
+                    return true;
+                } else {
+                    char error[100];
+                    snprintf(error, sizeof(error), "cannot find attribute %s in entity %s", attribute_s, command_s);
+                    output.clear();
+                    output["message"] = error;
+                    return false;
+                }
+            }
+
             return true;
         }
     }

src/test/test.cpp

@@ -660,9 +660,20 @@ void Test::run_test(uuid::console::Shell & shell, const std::string & cmd, const
         DynamicJsonDocument   doc(2000);
         JsonVariant           json;
         request.method(HTTP_GET);
+
+        request.url("/api/boiler/values");
+        EMSESP::webAPIService.webAPIService_get(&request);
         request.url("/api/boiler/wwcirc");
         EMSESP::webAPIService.webAPIService_get(&request);
-        request.url("/api/boiler/values");
+        request.url("/api/boiler/wwcirc/fullname");
+        EMSESP::webAPIService.webAPIService_get(&request);
+        request.url("/api/boiler/selburnpow/value");
+        EMSESP::webAPIService.webAPIService_get(&request);
+        request.url("/api/boiler/wwchargetype/writeable");
+        EMSESP::webAPIService.webAPIService_get(&request);
+        request.url("/api/boiler/flamecurr/value");
+        EMSESP::webAPIService.webAPIService_get(&request);
+        request.url("/api/boiler/flamecurr/bad");
         EMSESP::webAPIService.webAPIService_get(&request);
 #endif
     }

src/test/test.h

@@ -31,7 +31,7 @@ namespace emsesp {
 // #define EMSESP_DEBUG_DEFAULT "mixer"
 // #define EMSESP_DEBUG_DEFAULT "web"
 // #define EMSESP_DEBUG_DEFAULT "mqtt"
-#define EMSESP_DEBUG_DEFAULT "general"
+// #define EMSESP_DEBUG_DEFAULT "general"
 // #define EMSESP_DEBUG_DEFAULT "boiler"
 // #define EMSESP_DEBUG_DEFAULT "mqtt2"
 // #define EMSESP_DEBUG_DEFAULT "mqtt_nested"
@@ -48,7 +48,7 @@ namespace emsesp {
 // #define EMSESP_DEBUG_DEFAULT "2thermostats"
 // #define EMSESP_DEBUG_DEFAULT "dallas"
 // #define EMSESP_DEBUG_DEFAULT "analog"
-// #define EMSESP_DEBUG_DEFAULT "api_values"
+#define EMSESP_DEBUG_DEFAULT "api_values"
 // #define EMSESP_DEBUG_DEFAULT "mqtt_post"
 
 class Test {

src/version.h

@@ -1 +1 @@
-#define EMSESP_APP_VERSION "3.4.0b15"
+#define EMSESP_APP_VERSION "3.4.0b16"

src/web/WebAPIService.cpp

@@ -120,6 +120,15 @@ void WebAPIService::parse(AsyncWebServerRequest * request, JsonObject & input) {
         }
     }
 
+    // if we're returning single values, just sent as plain text
+    // https://github.com/emsesp/EMS-ESP32/issues/462#issuecomment-1093877210
+    if (output.containsKey("api_data")) {
+        JsonVariant data = output["api_data"];
+        request->send(200, "text/plain", data.as<String>());
+        api_count_++;
+        return;
+    }
+
     // send the json that came back from the command call
     // FAIL, OK, NOT_FOUND, ERROR, NOT_ALLOWED = 400 (bad request), 200 (OK), 400 (not found), 400 (bad request), 401 (unauthorized)
     int ret_codes[5] = {400, 200, 400, 400, 401};