Add schema validator example

example/CMakeLists.txt

@@ -9,6 +9,7 @@ set(EXAMPLES
     messagereader
     pretty
     prettyauto
+    schemavalidator
     serialize
     simpledom
     simplereader

example/schemavalidator/schemavalidator.cpp

+// Schema Validator example
+
+// The example validates JSON text from stdin with a JSON schema specified in the argument.
+
+#include "rapidjson/error/en.h"
+#include "rapidjson/filereadstream.h"
+#include "rapidjson/schema.h"
+#include "rapidjson/stringbuffer.h"
+
+using namespace rapidjson;
+
+int main(int argc, char *argv[]) {
+	if (argc != 2) {
+		fprintf(stderr, "Usage: schemavalidator schema.json < input.json\n");
+		return EXIT_FAILURE;
+	}
+
+	// Read a JSON schema from file into Document
+	Document d;
+	char buffer[4096];
+
+	{
+		FILE *fp = fopen(argv[1], "r");
+		if (!fp) {
+			printf("Schema file '%s' not found\n", argv[1]);
+			return -1;
+		}
+		FileReadStream fs(fp, buffer, sizeof(buffer));
+		d.ParseStream(fs);
+		if (d.HasParseError()) {
+			fprintf(stderr, "Schema file '%s' is not a valid JSON\n", argv[1]);
+		    fprintf(stderr, "Error(offset %u): %s\n",
+		    	static_cast<unsigned>(d.GetErrorOffset()),
+		    	GetParseError_En(d.GetParseError()));
+	    	fclose(fp);
+			return EXIT_FAILURE;
+		}
+		fclose(fp);
+	}
+	
+	// Then convert the Document into SchemaDocument
+	SchemaDocument sd(d);
+
+	// Use reader to parse the JSON in stdin, and forward SAX events to validator
+	SchemaValidator validator(sd);
+	Reader reader;
+	FileReadStream is(stdin, buffer, sizeof(buffer));
+	if (!reader.Parse(is, validator) && reader.GetParseErrorCode() != kParseErrorTermination) {
+		// Schema validator error would cause kParseErrorTermination, which will handle it in next step.
+		fprintf(stderr, "Input is not a valid JSON\n");
+	    fprintf(stderr, "Error(offset %u): %s\n",
+	    	static_cast<unsigned>(reader.GetErrorOffset()),
+	    	GetParseError_En(reader.GetParseErrorCode()));
+	}
+
+	// Check the validation result
+	if (validator.IsValid()) {
+		printf("Input JSON is valid.\n");
+		return EXIT_SUCCESS;
+	}
+	else {
+		printf("Input JSON is invalid.\n");
+        StringBuffer sb;
+        validator.GetInvalidSchemaPointer().StringifyUriFragment(sb);
+        fprintf(stderr, "Invalid schema: %s\n", sb.GetString());
+        fprintf(stderr, "Invalid keyword: %s\n", validator.GetInvalidSchemaKeyword());
+        sb.Clear();
+        validator.GetInvalidDocumentPointer().StringifyUriFragment(sb);
+        fprintf(stderr, "Invalid document: %s\n", sb.GetString());
+		return EXIT_FAILURE;
+	}
+}