Add --message-from-stdin flag for send command

README.md

@@ -25,7 +25,8 @@ System requirements:
 - at least Java Runtime Environment (JRE) 17
 - native library: libsignal-client
 
-  The native libs are bundled for x86_64 Linux (with recent enough glibc, see #643), Windows and MacOS. For other systems/architectures
+  The native libs are bundled for x86_64 Linux (with recent enough glibc, see #643), Windows and MacOS. For other
+  systems/architectures
   see: [Provide native lib for libsignal](https://github.com/AsamK/signal-cli/wiki/Provide-native-lib-for-libsignal)
 
 ### Install system-wide on Linux
@@ -75,7 +76,7 @@ of all country codes.)
 
 * Pipe the message content from another process.
 
-        uname -a | signal-cli -a ACCOUNT send RECIPIENT
+        uname -a | signal-cli -a ACCOUNT send --message-from-stdin RECIPIENT
 
 * Receive messages
 

man/signal-cli.1.adoc

@@ -212,7 +212,11 @@ Send the message to self without notification.
 Specify the recipient group ID in base64 encoding.
 
 *-m* MESSAGE, *--message* MESSAGE::
-Specify the message, if missing, standard input is used.
+Specify the message.
+Currently, signal-cli reads the message from stdin if `-m` is missing, but this will change in a future version and the explicit flag `--message-from-stdin` should be used instead.
+
+*--message-from-stdin*::
+Read the message from standard input.
 
 *-a* [ATTACHMENT [ATTACHMENT ...]], *--attachment* [ATTACHMENT [ATTACHMENT ...]]::
 Add one or more files as attachment.
@@ -578,7 +582,7 @@ Send a message to one or more recipients::
 signal-cli -a ACCOUNT send -m "This is a message" [RECIPIENT [RECIPIENT ...]] [-a [ATTACHMENT [ATTACHMENT ...]]]
 
 Pipe the message content from another process::
-uname -a | signal-cli -a ACCOUNT send [RECIPIENT [RECIPIENT ...]]
+uname -a | signal-cli -a ACCOUNT send --message-from-stdin [RECIPIENT [RECIPIENT ...]]
 
 Create a group::
 signal-cli -a ACCOUNT updateGroup -n "Group name" -m [MEMBER [MEMBER ...]]

src/main/java/org/asamk/signal/commands/SendCommand.java

@@ -51,7 +51,11 @@ public class SendCommand implements JsonRpcLocalCommand {
                 .help("Send the message to self without notification.")
                 .action(Arguments.storeTrue());
 
-        subparser.addArgument("-m", "--message").help("Specify the message, if missing standard input is used.");
+        var mut = subparser.addMutuallyExclusiveGroup();
+        mut.addArgument("-m", "--message").help("Specify the message to be sent.");
+        mut.addArgument("--message-from-stdin")
+                .action(Arguments.storeTrue())
+                .help("Read the message from standard input.");
         subparser.addArgument("-a", "--attachment").nargs("*").help("Add file as attachment");
         subparser.addArgument("-e", "--end-session", "--endsession")
                 .help("Clear session state and send end session message.")
@@ -107,10 +111,8 @@ public class SendCommand implements JsonRpcLocalCommand {
         final var sticker = stickerString == null ? null : parseSticker(stickerString);
 
         var messageText = ns.getString("message");
-        if (messageText == null) {
+        final var readMessageFromStdin = ns.getBoolean("message-from-stdin") == Boolean.TRUE;
-            if (sticker != null) {
+        if (readMessageFromStdin || (messageText == null && sticker == null)) {
-                messageText = "";
-            } else {
             logger.debug("Reading message from stdin...");
             try {
                 messageText = IOUtils.readAll(System.in, Charset.defaultCharset());
@@ -118,7 +120,6 @@ public class SendCommand implements JsonRpcLocalCommand {
                 throw new UserErrorException("Failed to read message from stdin: " + e.getMessage());
             }
         }
-        }
 
         List<String> attachments = ns.getList("attachment");
         if (attachments == null) {
@@ -146,7 +147,7 @@ public class SendCommand implements JsonRpcLocalCommand {
         }
 
         try {
-            var results = m.sendMessage(new Message(messageText,
+            var results = m.sendMessage(new Message(messageText == null ? "" : messageText,
                     attachments,
                     mentions,
                     Optional.ofNullable(quote),