Example

git-svn-id: https://svn.kapsi.fi/jpa/nanopb@957 e3a754e5-d11d-0410-8d38-ebb782a927b9

example/Makefile

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+CFLAGS=-ansi -Wall -Werror -I .. -g -O0
+DEPS=../pb_decode.c ../pb_decode.h ../pb_encode.c ../pb_encode.h ../pb.h
+
+all: server
+
+%: %.c $(DEPS) fileproto.h
+	$(CC) $(CFLAGS) -o $@ $< ../pb_decode.c ../pb_encode.c fileproto.c
+
+fileproto.h: fileproto.proto ../generator/nanopb_generator.py
+	protoc -I. -I../generator -I/usr/include -ofileproto.pb $<
+	python ../generator/nanopb_generator.py fileproto.pb

example/fileproto.proto

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+import "nanopb.proto";
+
+// This defines protocol for a simple server that lists files.
+//
+// If you come from high-level programming background, the hardcoded
+// maximum lengths may disgust you. However, if your microcontroller only
+// has a few kB of ram to begin with, setting reasonable limits for
+// filenames is ok.
+//
+// On the other hand, using the callback interface, it is not necessary
+// to set a limit on the number of files in the response.
+
+message ListFilesRequest {
+    optional string path = 1 [default = "/", (nanopb).max_size = 128];
+}
+
+message FileInfo {
+    required uint64 inode = 1;
+    required string name = 2 [(nanopb).max_size = 128];
+}
+
+message ListFilesResponse {
+    optional bool path_error = 1 [default = false];
+    repeated FileInfo file = 2;
+}
+

example/server.c

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+/* This is a simple TCP server that listens on port 1234 and provides lists
+ * of files to clients, using a protocol defined in file_server.proto.
+ *
+ * It directly deserializes and serializes messages from network, minimizing
+ * memory use.
+ * 
+ * For flexibility, this example is implemented using posix api.
+ * In a real embedded system you would typically use some other kind of
+ * a communication and filesystem layer.
+ */
+
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <netinet/in.h>
+#include <unistd.h>
+#include <dirent.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <pb_encode.h>
+#include <pb_decode.h>
+
+#include "fileproto.h"
+
+bool write_callback(pb_ostream_t *stream, const uint8_t *buf, size_t count)
+{
+    int fd = *(int*)stream->state;
+    return send(fd, buf, count, 0) == count;
+}
+
+bool read_callback(pb_istream_t *stream, uint8_t *buf, size_t count)
+{
+    int fd = *(int*)stream->state;
+    
+    if (buf == NULL)
+    {
+        /* Well, this is a really inefficient way to skip input. */
+        /* It is only used when there are unknown fields. */
+        char dummy;
+        while (count-- && recv(fd, &dummy, 1, 0) == 1);
+        return count == 0;
+    }
+    
+    return recv(fd, buf, count, MSG_WAITALL) == count;
+}
+
+bool listdir_callback(pb_ostream_t *stream, const pb_field_t *field, const void *arg)
+{
+    DIR *dir = (DIR*) arg;
+    struct dirent *file;
+    FileInfo fileinfo;
+    
+    while ((file = readdir(dir)) != NULL)
+    {
+        fileinfo.inode = file->d_ino;
+        strncpy(fileinfo.name, file->d_name, sizeof(fileinfo.name));
+        fileinfo.name[sizeof(fileinfo.name) - 1] = '\0';
+        
+        if (!pb_encode_tag_for_field(stream, field))
+            return false;
+        
+        if (!pb_enc_submessage(stream, field, &fileinfo))
+            return false;
+    }
+    
+    return true;
+}
+
+void handle_connection(int connfd)
+{
+    ListFilesRequest request;
+    ListFilesResponse response;
+    pb_istream_t input = {&read_callback, &connfd, SIZE_MAX};
+    pb_ostream_t output = {&write_callback, &connfd, SIZE_MAX, 0};
+    DIR *directory;
+    
+    if (!pb_decode(&input, ListFilesRequest_fields, &request))
+    {
+        printf("Decoding failed.\n");
+        return;
+    }
+    
+    directory = opendir(request.path);
+    
+    printf("Listing directory: %s\n", request.path);
+    
+    if (directory == NULL)
+    {
+        perror("opendir");
+        
+        response.has_path_error = true;
+        response.path_error = true;
+        response.file.funcs.encode = NULL;
+    }
+    else
+    {
+        response.has_path_error = false;
+        response.file.funcs.encode = &listdir_callback;
+        response.file.arg = directory;
+    }
+    
+    if (!pb_encode(&output, ListFilesResponse_fields, &response))
+    {
+        printf("Encoding failed.\n");
+    }
+}
+
+int main(int argc, char **argv)
+{
+    int listenfd, connfd;
+    struct sockaddr_in servaddr;
+    
+    listenfd = socket(AF_INET, SOCK_STREAM, 0);
+    
+    memset(&servaddr, 0, sizeof(servaddr));
+    servaddr.sin_family = AF_INET;
+    servaddr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+    servaddr.sin_port = htons(1234);
+    if (bind(listenfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) != 0)
+    {
+        perror("bind");
+        return 1;
+    }
+    
+    if (listen(listenfd, 5) != 0)
+    {
+        perror("listen");
+        return 1;
+    }
+    
+    for(;;)
+    {
+        connfd = accept(listenfd, NULL, NULL);
+        
+        if (connfd < 0)
+        {
+            perror("accept");
+            return 1;
+        }
+        
+        printf("Got connection.\n");
+        
+        handle_connection(connfd);
+        
+        printf("Closing connection.\n");
+        
+        close(connfd);
+    }
+}