Add file transfer example

examples/file-transfer/Makefile

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+SPROG ?= server                   # Program we are building
+CPROG ?= client                   # Program we are building
+DELETE = rm -rf                   # Command to remove files
+SOUT ?= -o $(SPROG)               # Compiler argument for output file
+COUT ?= -o $(CPROG)               # Compiler argument for output file
+SSOURCES = server.c mongoose.c    # Source code files
+CSOURCES = client.c mongoose.c    # Source code files
+CFLAGS = -W -Wall -Wextra -g -I.  # Build options
+
+# Mongoose build options. See https://mongoose.ws/documentation/#build-options
+#CFLAGS_MONGOOSE += -DMG_ENABLE_LINES
+
+ifeq ($(OS),Windows_NT)   # Windows settings. Assume MinGW compiler. To use VC: make CC=cl CFLAGS=/MD OUT=/Feprog.exe
+  SPROG ?= server.exe             # Use .exe suffix for the binary
+  CPROG ?= client.exe             # Use .exe suffix for the binary
+  CC = gcc                        # Use MinGW gcc compiler
+  CFLAGS += -lws2_32              # Link against Winsock library
+  DELETE = cmd /C del /Q /F /S    # Command prompt command to delete files
+  SOUT ?= -o $(SPROG)             # Build output
+  COUT ?= -o $(CPROG)             # Build output
+endif
+
+all: example                      # Default target. Build all and run server
+	$(RUN) ./$(SPROG) $(SARGS)
+
+example: $(SPROG) $(CPROG)            
+
+$(SPROG): $(SSOURCES)       # Build program from sources
+	$(CC) $(SSOURCES) $(CFLAGS) $(CFLAGS_MONGOOSE) $(CFLAGS_EXTRA) $(SOUT)
+
+$(CPROG): $(CSOURCES)       # Build program from sources
+	$(CC) $(CSOURCES) $(CFLAGS) $(CFLAGS_MONGOOSE) $(CFLAGS_EXTRA) $(COUT)
+
+clean:                      # Cleanup. Delete built program and all build artifacts
+	$(DELETE) $(SPROG) $(CPROG) *.o *.obj *.exe *.dSYM

examples/file-transfer/README.md

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+# File Transfer
+
+This example contains minimal HTTP client and server.
+
+The client uploads a file to the server in a single POST, shaping traffic to send small data chunks.
+
+The server manually processes requests in order to be able to write as soon as data arrives, to avoid buffering a whole (possibly huge) file not fitting in RAM.
+
+Uploads are authenticated using Basic Auth. Both client and server have a default user/pass and can be configured using the command line. Only authenticated users can upload a file.
+
+The server can also accept regular uploads from any HTTP client, for example curl:
+
+```sh
+	curl -su user:pass  http://localhost:8090/upload/foo.txt --data-binary @Makefile
+```
+
+- Follow the [Build Tools](../tools/) tutorial to setup your development environment.
+- Start a terminal in this project directory; and build the example:
+
+  ```sh
+  cd mongoose/examples/file-transfer
+  make clean all
+  ```
+
+- Manually start the server, either in background (to reuse the same terminal window) or in foreground; in which case you'll need another terminal to run the client. The server will listen at all interfaces in port 8090
+
+  ```sh
+  ./server
+  6332b7 2 server.c:157:main              Mongoose version : v7.12
+  6332b7 2 server.c:158:main              Listening on     : http://0.0.0.0:8090
+  6332b7 2 server.c:159:main              Web root         : [/home/mongoose/examples/file-transfer/web_root]
+  6332b7 2 server.c:160:main              Uploading to     : [/home/mongoose/examples/file-transfer/upload]
+  ```
+
+- Manually run the client to send a file, default is to send it as "foo.txt" to the server in localhost at port 8090
+
+  ```sh
+  ./client -f Makefile
+  ok
+  ```
+
+Default operation is to assume hardcoded username and password. Call both server and client with no arguments to see usage instructions
+
+See detailed tutorials at
+	https://mongoose.ws/tutorials/file-uploads/
+	https://mongoose.ws/tutorials/http-server/
+	https://mongoose.ws/tutorials/http-client/

examples/file-transfer/client.c

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+// Copyright (c) 2021 Cesanta Software Limited
+// All rights reserved
+//
+// Example HTTP client. Connect to `s_url`, send request, wait for a response,
+// print the response and exit.
+// You can change `s_url` from the command line by executing: ./example YOUR_URL
+//
+// To enable SSL/TLS, , see https://mongoose.ws/tutorials/tls/#how-to-build
+
+#include "mongoose.h"
+
+static int s_debug_level = MG_LL_INFO;
+static const char *s_user = "user";
+static const char *s_pass = "pass";
+static const char *s_fname = NULL;
+static struct mg_fd *fd;  // file descriptor
+static size_t fsize;
+static const char *s_url = "http://localhost:8090/upload/foo.txt";
+static const uint64_t s_timeout_ms = 1500;  // Connect timeout in milliseconds
+
+// Print HTTP response and signal that we're done
+static void fn(struct mg_connection *c, int ev, void *ev_data) {
+  if (ev == MG_EV_OPEN) {
+    // Connection created. Store connect expiration time in c->data
+    *(uint64_t *) c->data = mg_millis() + s_timeout_ms;
+  } else if (ev == MG_EV_POLL) {
+    if (mg_millis() > *(uint64_t *) c->data &&
+        (c->is_connecting || c->is_resolving)) {
+      mg_error(c, "Connect timeout");
+    }
+  } else if (ev == MG_EV_CONNECT) {
+    // Connected to server. Extract host name from URL
+    struct mg_str host = mg_url_host(s_url);
+    // Send request
+    MG_DEBUG(("Connected, send request"));
+    mg_printf(c,
+              "POST %s HTTP/1.0\r\n"
+              "Host: %.*s\r\n"
+              "Content-Type: octet-stream\r\n"
+              "Content-Length: %d\r\n",
+              mg_url_uri(s_url), (int) host.len, host.ptr, fsize);
+    mg_http_bauth(c, s_user, s_pass);  // Add Basic auth header
+    mg_printf(c, "%s", "\r\n");        // End HTTP headers
+  } else if (ev == MG_EV_WRITE && c->send.len < MG_IO_SIZE) {
+    uint8_t *buf = alloca(MG_IO_SIZE);
+    size_t len = MG_IO_SIZE - c->send.len;
+    len = fsize < len ? fsize : len;
+    fd->fs->rd(fd->fd, buf, len);
+    mg_send(c, buf, len);
+    fsize -= len;
+    MG_DEBUG(("sent %u bytes", len));
+  } else if (ev == MG_EV_HTTP_MSG) {
+    MG_DEBUG(("MSG"));
+    // Response is received. Print it
+    struct mg_http_message *hm = (struct mg_http_message *) ev_data;
+    printf("%.*s", (int) hm->body.len, hm->body.ptr);
+    c->is_draining = 1;  // Tell mongoose to close this connection
+    mg_fs_close(fd);
+    *(bool *) c->fn_data = true;  // Tell event loop to stop
+  } else if (ev == MG_EV_ERROR) {
+    MG_DEBUG(("ERROR"));
+    mg_fs_close(fd);
+    *(bool *) c->fn_data = true;  // Error, tell event loop to stop
+  }
+}
+
+static void usage(const char *prog) {
+  fprintf(stderr,
+          "File Transfer client based on Mongoose v.%s\n"
+          "Usage: %s -f NAME OPTIONS\n"
+          "  -u NAME   - user name, default: '%s'\n"
+          "  -p PWD    - password, default: '%s'\n"
+          "  -U URL    - Full server URL, including destination file name; "
+          "default: '%s'\n"
+          "  -f NAME   - File to send\n"
+          "  -v LEVEL  - debug level, from 0 to 4, default: %d\n",
+          MG_VERSION, prog, s_user, s_pass, s_url, s_debug_level);
+  exit(EXIT_FAILURE);
+}
+
+int main(int argc, char *argv[]) {
+  struct mg_mgr mgr;  // Event manager
+  bool done = false;  // Event handler flips it to true
+  time_t mtime;
+  int i;
+
+  // Parse command-line flags
+  for (i = 1; i < argc; i++) {
+    if (strcmp(argv[i], "-f") == 0) {
+      s_fname = argv[++i];
+    } else if (strcmp(argv[i], "-u") == 0) {
+      s_user = argv[++i];
+    } else if (strcmp(argv[i], "-p") == 0) {
+      s_pass = argv[++i];
+    } else if (strcmp(argv[i], "-U") == 0) {
+      s_url = argv[++i];
+    } else if (strcmp(argv[i], "-v") == 0) {
+      s_debug_level = atoi(argv[++i]);
+    } else {
+      usage(argv[0]);
+    }
+  }
+  if (s_fname == NULL) usage(argv[0]);
+  mg_fs_posix.st(s_fname, &fsize, &mtime);
+  if (fsize == 0 ||
+      (fd = mg_fs_open(&mg_fs_posix, s_fname, MG_FS_READ)) == NULL) {
+    MG_ERROR(("open failed: %d", errno));
+    exit(EXIT_FAILURE);
+  }
+
+  mg_log_set(s_debug_level);
+  mg_mgr_init(&mgr);                        // Initialise event manager
+  mg_http_connect(&mgr, s_url, fn, &done);  // Create client connection
+  while (!done) mg_mgr_poll(&mgr, 50);      // Event manager loops until 'done'
+  mg_mgr_free(&mgr);                        // Free resources
+  return 0;
+}

examples/file-transfer/mongoose.c

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+../../mongoose.c

examples/file-transfer/mongoose.h

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+../../mongoose.h

examples/file-transfer/server.c

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+// Copyright (c) 2024 Cesanta Software Limited
+// All rights reserved
+
+#include <signal.h>
+#include "mongoose.h"
+
+static int s_debug_level = MG_LL_INFO;
+static int s_max_size = 10000;
+static const char *s_root_dir = "web_root";
+static const char *s_upld_dir = "upload";
+static const char *s_listening_address = "http://0.0.0.0:8090";
+static const char *s_user = "user";
+static const char *s_pass = "pass";
+
+// Handle interrupts, like Ctrl-C
+static int s_signo;
+static void signal_handler(int signo) {
+  s_signo = signo;
+}
+
+static bool authuser(struct mg_http_message *hm) {
+  char user[256], pass[256];
+  mg_http_creds(hm, user, sizeof(user), pass, sizeof(pass));
+  if (strcmp(user, s_user) == 0 && strcmp(pass, s_pass) == 0) return true;
+  return false;
+}
+
+// Streaming upload example. Demonstrates how to use MG_EV_READ events
+// to get large payload in smaller chunks. To test, use curl utility:
+static void cb(struct mg_connection *c, int ev, void *ev_data) {
+  if (ev == MG_EV_READ) {
+    // Parse the incoming data ourselves. If we can parse the request,
+    // store two size_t variables in c->data: expected len and recv len.
+    size_t *data = (size_t *) c->data;
+    struct mg_fd *fd = (struct mg_fd *) c->fn_data;  // get file descriptor
+    if (data[0]) {  // Already parsed, receiving body
+      data[1] += c->recv.len;
+      MG_DEBUG(("Got chunk len %lu, %lu total", c->recv.len, data[1]));
+      fd->fs->wr(fd->fd, c->recv.buf, c->recv.len);
+      c->recv.len = 0;  // And cleanup the receive buffer. Streaming!
+      if (data[1] >= data[0]) {
+        mg_fs_close(fd);
+        mg_http_reply(c, 200, "", "ok\n");
+      }
+    } else if(c->is_resp == 0) {
+      struct mg_http_message hm;
+      int n = mg_http_parse((char *) c->recv.buf, c->recv.len, &hm);
+      if (n < 0) mg_error(c, "Bad response");
+      if (n > 0) {
+        if (mg_http_match_uri(&hm, "/upload/#")) {
+          if (!authuser(&hm)) {
+            mg_http_reply(c, 403, "", "Denied\n");
+            c->is_draining = 1;  // Tell mongoose to close this connection
+          } else if (hm.body.len > (size_t) s_max_size) {
+            mg_http_reply(c, 400, "", "Too long\n");
+            c->is_draining = 1;  // Tell mongoose to close this connection
+          } else if (hm.uri.len == 8) {  // 8: /upload/
+            mg_http_reply(c, 400, "", "Name required\n");
+            c->is_draining = 1;  // Tell mongoose to close this connection
+          } else if (strlen(s_upld_dir) + (hm.uri.len - 8) + 2 >
+                     MG_PATH_MAX) {  // 2: MG_DIRSEP + NUL
+            mg_http_reply(c, 400, "", "Path is too long\n");
+            c->is_draining = 1;  // Tell mongoose to close this connection
+          } else {
+            char fpath[MG_PATH_MAX];
+            snprintf(fpath, MG_PATH_MAX, "%s%c", s_upld_dir, MG_DIRSEP);
+            strncat(fpath, hm.uri.ptr + 8, hm.uri.len - 8);
+            if (!mg_path_is_sane(fpath)) {
+              mg_http_reply(c, 400, "", "Invalid path\n");
+              c->is_draining = 1;  // Tell mongoose to close this connection
+            } else {
+              MG_DEBUG(("Got request, chunk len %lu", c->recv.len - n));
+              if ((fd = mg_fs_open(&mg_fs_posix, fpath, MG_FS_WRITE)) == NULL) {
+                mg_http_reply(c, 400, "", "open failed: %d", errno);
+                c->is_draining = 1;  // Tell mongoose to close this connection
+            } else {
+                c->fn_data = fd;
+                c->recv.len -= n;  // remove headers
+                data[0] = hm.body.len;
+                data[1] = c->recv.len;
+                if (c->recv.len)
+                  fd->fs->wr(fd->fd, c->recv.buf + n, c->recv.len);
+                c->recv.len = 0;  // consume data
+                if (data[1] >= data[0]) {
+                  mg_fs_close(fd);
+                  mg_http_reply(c, 200, "", "ok\n");
+                }
+              }
+            }
+          }
+          c->is_resp = 1;    // ignore the rest of the body
+        } else {
+          struct mg_http_serve_opts opts = {0};
+          opts.root_dir = s_root_dir;
+          mg_http_serve_dir(c, &hm, &opts);
+        }
+      }
+    }
+  }
+  (void) ev_data;
+}
+
+static void usage(const char *prog) {
+  fprintf(stderr,
+          "File Transfer server based on Mongoose v.%s\n"
+          "Usage: %s OPTIONS\n"
+          "  -u NAME   - user name, default: '%s'\n"
+          "  -p PWD    - password, default: '%s'\n"
+          "  -d DIR    - directory to serve, default: '%s'\n"
+          "  -D DIR    - directory to store uploads, default: '%s'\n"
+          "  -s SIZE   - maximum allowed file size, default: '%d'\n"
+          "  -l ADDR   - listening address, default: '%s'\n"
+          "  -v LEVEL  - debug level, from 0 to 4, default: %d\n",
+          MG_VERSION, prog, s_user, s_pass, s_root_dir, s_upld_dir, s_max_size,
+          s_listening_address, s_debug_level);
+  exit(EXIT_FAILURE);
+}
+
+int main(int argc, char *argv[]) {
+  char spath[MG_PATH_MAX] = ".";
+  char upath[MG_PATH_MAX] = ".";
+  struct mg_mgr mgr;
+  int i;
+
+  // Parse command-line flags
+  for (i = 1; i < argc; i++) {
+    if (strcmp(argv[i], "-d") == 0) {
+      s_root_dir = argv[++i];
+    } else if (strcmp(argv[i], "-D") == 0) {
+      s_upld_dir = argv[++i];
+    } else if (strcmp(argv[i], "-u") == 0) {
+      s_user = argv[++i];
+    } else if (strcmp(argv[i], "-p") == 0) {
+      s_pass = argv[++i];
+    } else if (strcmp(argv[i], "-l") == 0) {
+      s_listening_address = argv[++i];
+    } else if (strcmp(argv[i], "-v") == 0) {
+      s_debug_level = atoi(argv[++i]);
+    } else if (strcmp(argv[i], "-s") == 0) {
+      s_max_size = atoi(argv[++i]);
+    } else {
+      usage(argv[0]);
+    }
+  }
+
+  // Root directory must not contain double dots. Make it absolute
+  // Do the conversion only if the root dir spec does not contain overrides
+  if (strchr(s_root_dir, ',') == NULL) {
+    realpath(s_root_dir, spath);
+    s_root_dir = spath;
+  }
+  if (strchr(s_upld_dir, ',') == NULL) {
+    realpath(s_upld_dir, upath);
+    s_upld_dir = upath;
+  }
+
+  // Initialise stuff
+  signal(SIGINT, signal_handler);
+  signal(SIGTERM, signal_handler);
+  mg_log_set(s_debug_level);
+  mg_mgr_init(&mgr);
+  if (mg_http_listen(&mgr, s_listening_address, cb, NULL) == NULL) {
+    MG_ERROR(("Cannot listen on %s.", s_listening_address));
+    exit(EXIT_FAILURE);
+  }
+
+  // Start infinite event loop
+  MG_INFO(("Mongoose version : v%s", MG_VERSION));
+  MG_INFO(("Listening on     : %s", s_listening_address));
+  MG_INFO(("Web root         : [%s]", s_root_dir));
+  MG_INFO(("Uploading to     : [%s]", s_upld_dir));
+  while (s_signo == 0) mg_mgr_poll(&mgr, 1000);
+  mg_mgr_free(&mgr);
+  MG_INFO(("Exiting on signal %d", s_signo));
+  return 0;
+}

examples/file-transfer/web_root/index.html

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+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <title>File Transfer</title>
+  </head>
+  <body>
+    <p style="font-size:100px">&#128515;</p>
+  </body>
+</html>