Improve webserver page

2025-12-19 13:49:26 +00:00 · 2021-01-30 10:07:17 +00:00
parent b732ade9e1
commit 8f9133bcc2
4 changed files with 203 additions and 18 deletions
--- a/include/ESPTemplateProcessor.h
+++ b/include/ESPTemplateProcessor.h
@@ -0,0 +1,116 @@
+#ifndef ESP_TEMPLATE_PROCESSOR_H
+#define ESP_TEMPLATE_PROCESSOR_H
+
+#ifdef ESP8266
+#define WebServer ESP8266WebServer
+#include <ESP8266WebServer.h>
+#else
+#include <WebServer.h>
+#endif
+
+#include <LittleFS.h>
+
+typedef String ProcessorCallback(const String& key);
+
+class ESPTemplateProcessor {
+  public:
+    ESPTemplateProcessor(WebServer& _server) :
+      server(_server)
+    {
+    }
+
+    bool send(const String& filePath, ProcessorCallback& processor, char bookend = '~', bool silentSerial = false)
+    {
+      // Open file.
+      if(!LittleFS.exists(filePath)) {
+        if(!silentSerial) {
+          Serial.print("Cannot process "); Serial.print(filePath); Serial.println(": Does not exist.");
+        }
+        return false;
+      }
+
+      File file = LittleFS.open(filePath, "r");
+      if (!file) {
+        if(!silentSerial) {
+          Serial.print("Cannot process "); Serial.print(filePath); Serial.println(": Failed to open.");
+        }
+        return false;
+      }
+
+      server.setContentLength(CONTENT_LENGTH_UNKNOWN);
+      server.sendHeader("Content-Type","text/html",true);
+      server.sendHeader("Cache-Control","no-cache");
+      server.send(200);
+      //server.sendContent(<chunk>)
+
+      // Process!
+      static const uint16_t MAX = 100;
+      String buffer;
+      int bufferLen = 0;
+      String keyBuffer;
+      int val;
+      char ch;
+      while ((val = file.read()) != -1) {
+        ch = char(val);
+        
+        // Lookup expansion.
+        if (ch == bookend) {
+          // Clear out buffer.
+          server.sendContent(buffer);
+          buffer = "";
+          bufferLen = 0;
+
+          // Process substitution.
+          keyBuffer = "";
+          bool found = false;
+          while (!found && (val = file.read()) != -1) {
+            ch = char(val);
+            if (ch == bookend) {
+              found = true;
+            } else {
+              keyBuffer += ch;
+            }
+          }
+          
+          // Check for bad exit.
+          if (val == -1 && !found) {
+            if(!silentSerial) {
+              Serial.print("Cannot process "); Serial.print(filePath); Serial.println(": Unable to parse.");
+            }
+            return false;
+          }
+
+          // Get substitution
+          String processed = processor(keyBuffer);
+          if(!silentSerial) {
+            Serial.print("Lookup '"); Serial.print(keyBuffer); Serial.print("' received: "); Serial.println(processed);
+          }
+          server.sendContent(processed);
+        } else {
+          bufferLen++;
+          buffer += ch;
+          if (bufferLen >= MAX) {
+            server.sendContent(buffer);
+            bufferLen = 0;
+            buffer = "";
+          }
+        }
+      }
+
+      if (val == -1) {
+        server.sendContent(buffer);
+        server.sendContent("");
+        return true;
+      } else {
+        if(!silentSerial) {
+          Serial.print("Failed to process '"); Serial.print(filePath); Serial.println("': Didn't reach the end of the file.");
+        }
+      }
+    }
+
+
+  private:
+    WebServer &server;
+};
+
+#endif