Move examples into subfolders, add READMEs

examples/network_server/Makefile

@@ -0,0 +1,19 @@
+CFLAGS = -ansi -Wall -Werror -g -O0
+
+# Path to the nanopb root folder
+NANOPB_DIR = ../..
+DEPS = $(NANOPB_DIR)/pb_decode.c $(NANOPB_DIR)/pb_decode.h \
+       $(NANOPB_DIR)/pb_encode.c $(NANOPB_DIR)/pb_encode.h $(NANOPB_DIR)/pb.h
+CFLAGS += -I$(NANOPB_DIR)
+
+all: server client
+
+clean:
+	rm -f server client fileproto.pb.c fileproto.pb.h
+
+%: %.c $(DEPS) fileproto.pb.h fileproto.pb.c
+	$(CC) $(CFLAGS) -o $@ $< $(NANOPB_DIR)/pb_decode.c $(NANOPB_DIR)/pb_encode.c fileproto.pb.c common.c
+
+fileproto.pb.c fileproto.pb.h: fileproto.proto $(NANOPB_DIR)/generator/nanopb_generator.py
+	protoc -ofileproto.pb $<
+	python $(NANOPB_DIR)/generator/nanopb_generator.py fileproto.pb

examples/network_server/README

@@ -0,0 +1,60 @@
+Nanopb example "network_server"
+===============================
+
+This example demonstrates the use of nanopb to communicate over network
+connections. It consists of a server that sends file listings, and of
+a client that requests the file list from the server.
+
+Example usage
+-------------
+
+user@host:~/nanopb/examples/network_server$ make        # Build the example
+protoc -ofileproto.pb fileproto.proto
+python ../../generator/nanopb_generator.py fileproto.pb
+Writing to fileproto.pb.h and fileproto.pb.c
+cc -ansi -Wall -Werror -I .. -g -O0 -I../.. -o server server.c
+    ../../pb_decode.c ../../pb_encode.c fileproto.pb.c common.c
+cc -ansi -Wall -Werror -I .. -g -O0 -I../.. -o client client.c
+    ../../pb_decode.c ../../pb_encode.c fileproto.pb.c common.c
+
+user@host:~/nanopb/examples/network_server$ ./server &  # Start the server on background
+[1] 24462
+
+petteri@oddish:~/nanopb/examples/network_server$ ./client /bin  # Request the server to list /bin
+Got connection.
+Listing directory: /bin
+1327119    bzdiff
+1327126    bzless
+1327147    ps
+1327178    ntfsmove
+1327271    mv
+1327187    mount
+1327259    false
+1327266    tempfile
+1327285    zfgrep
+1327165    gzexe
+1327204    nc.openbsd
+1327260    uname
+
+
+Details of implementation
+-------------------------
+fileproto.proto contains the portable Google Protocol Buffers protocol definition.
+It could be used as-is to implement a server or a client in any other language, for
+example Python or Java.
+
+fileproto.options contains the nanopb-specific options for the protocol file. This
+sets the amount of space allocated for file names when decoding messages.
+
+common.c/h contains functions that allow nanopb to read and write directly from
+network socket. This way there is no need to allocate a separate buffer to store
+the message.
+
+server.c contains the code to open a listening socket, to respond to clients and
+to list directory contents.
+
+client.c contains the code to connect to a server, to send a request and to print
+the response message.
+
+The code is implemented using the POSIX socket api, but it should be easy enough
+to port into any other socket api, such as lwip.

examples/network_server/client.c

@@ -0,0 +1,116 @@
+/* This is a simple TCP client that connects to port 1234 and prints a list
+ * of files in a given directory.
+ *
+ * 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.pb.h"
+#include "common.h"
+
+bool printfile_callback(pb_istream_t *stream, const pb_field_t *field, void **arg)
+{
+    FileInfo fileinfo;
+    
+    if (!pb_decode(stream, FileInfo_fields, &fileinfo))
+        return false;
+    
+    printf("%-10lld %s\n", (long long)fileinfo.inode, fileinfo.name);
+    
+    return true;
+}
+
+bool listdir(int fd, char *path)
+{
+    ListFilesRequest request;
+    ListFilesResponse response;
+    pb_istream_t input = pb_istream_from_socket(fd);
+    pb_ostream_t output = pb_ostream_from_socket(fd);
+    uint8_t zero = 0;
+    
+    if (path == NULL)
+    {
+        request.has_path = false;
+    }
+    else
+    {
+        request.has_path = true;
+        if (strlen(path) + 1 > sizeof(request.path))
+        {
+            fprintf(stderr, "Too long path.\n");
+            return false;
+        }
+        
+        strcpy(request.path, path);
+    }
+    
+    if (!pb_encode(&output, ListFilesRequest_fields, &request))
+    {
+        fprintf(stderr, "Encoding failed.\n");
+        return false;
+    }
+    
+    /* We signal the end of request with a 0 tag. */
+    pb_write(&output, &zero, 1);
+    
+    response.file.funcs.decode = &printfile_callback;
+    
+    if (!pb_decode(&input, ListFilesResponse_fields, &response))
+    {
+        fprintf(stderr, "Decode failed: %s\n", PB_GET_ERROR(&input));
+        return false;
+    }
+    
+    if (response.path_error)
+    {
+        fprintf(stderr, "Server reported error.\n");
+        return false;
+    }
+    
+    return true;
+}
+
+int main(int argc, char **argv)
+{
+    int sockfd;
+    struct sockaddr_in servaddr;
+    char *path = NULL;
+    
+    if (argc > 1)
+        path = argv[1];
+    
+    sockfd = 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 (connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) != 0)
+    {
+        perror("connect");
+        return 1;
+    }
+    
+    if (!listdir(sockfd, path))
+        return 2;
+    
+    close(sockfd);
+    
+    return 0;
+}

examples/network_server/common.c

@@ -0,0 +1,40 @@
+/* Simple binding of nanopb streams to TCP sockets.
+ */
+
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <pb_encode.h>
+#include <pb_decode.h>
+
+#include "common.h"
+
+static bool write_callback(pb_ostream_t *stream, const uint8_t *buf, size_t count)
+{
+    int fd = (intptr_t)stream->state;
+    return send(fd, buf, count, 0) == count;
+}
+
+static bool read_callback(pb_istream_t *stream, uint8_t *buf, size_t count)
+{
+    int fd = (intptr_t)stream->state;
+    int result;
+    
+    result = recv(fd, buf, count, MSG_WAITALL);
+    
+    if (result == 0)
+        stream->bytes_left = 0; /* EOF */
+    
+    return result == count;
+}
+
+pb_ostream_t pb_ostream_from_socket(int fd)
+{
+    pb_ostream_t stream = {&write_callback, (void*)(intptr_t)fd, SIZE_MAX, 0};
+    return stream;
+}
+
+pb_istream_t pb_istream_from_socket(int fd)
+{
+    pb_istream_t stream = {&read_callback, (void*)(intptr_t)fd, SIZE_MAX};
+    return stream;
+}

examples/network_server/common.h

@@ -0,0 +1,9 @@
+#ifndef _PB_EXAMPLE_COMMON_H_
+#define _PB_EXAMPLE_COMMON_H_
+
+#include <pb.h>
+
+pb_ostream_t pb_ostream_from_socket(int fd);
+pb_istream_t pb_istream_from_socket(int fd);
+
+#endif

examples/network_server/fileproto.options

@@ -0,0 +1,13 @@
+# This file defines the nanopb-specific options for the messages defined
+# in fileproto.proto.
+#
+# 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.
+
+ListFilesRequest.path 	max_size:128
+FileInfo.name 		max_size:128

examples/network_server/fileproto.proto

@@ -0,0 +1,18 @@
+// This defines protocol for a simple server that lists files.
+//
+// See also the nanopb-specific options in fileproto.options.
+
+message ListFilesRequest {
+    optional string path = 1 [default = "/"];
+}
+
+message FileInfo {
+    required uint64 inode = 1;
+    required string name = 2;
+}
+
+message ListFilesResponse {
+    optional bool path_error = 1 [default = false];
+    repeated FileInfo file = 2;
+}
+

examples/network_server/server.c

@@ -0,0 +1,131 @@
+/* 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.pb.h"
+#include "common.h"
+
+bool listdir_callback(pb_ostream_t *stream, const pb_field_t *field, void * const *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_encode_submessage(stream, FileInfo_fields, &fileinfo))
+            return false;
+    }
+    
+    return true;
+}
+
+void handle_connection(int connfd)
+{
+    ListFilesRequest request;
+    ListFilesResponse response;
+    pb_istream_t input = pb_istream_from_socket(connfd);
+    pb_ostream_t output = pb_ostream_from_socket(connfd);
+    DIR *directory;
+    
+    if (!pb_decode(&input, ListFilesRequest_fields, &request))
+    {
+        printf("Decode failed: %s\n", PB_GET_ERROR(&input));
+        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;
+    int reuse = 1;
+    
+    listenfd = socket(AF_INET, SOCK_STREAM, 0);
+    
+    setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(reuse));
+    
+    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);
+    }
+}