91 lines
4.4 KiB
Markdown
91 lines
4.4 KiB
Markdown
<h1> Message Subsystem</h1>
|
|
|
|
<h2>Table of Contents</h2>
|
|
|
|
- [Introduction](#introduction)
|
|
- [Curl Examples](#curl-examples)
|
|
- [Mycelium Binary Examples](#mycelium-binary-examples)
|
|
|
|
***
|
|
|
|
## Introduction
|
|
|
|
The message subsystem can be used to send arbitrary length messages to receivers. A receiver is any
|
|
other node in the network. It can be identified both by its public key, or an IP address in its announced
|
|
range. The message subsystem can be interacted with both via the HTTP API, which is
|
|
[documented here](api_yaml.md), or via the `mycelium` binary. By default, the messages do not interpret
|
|
the data in any way. When using the binary, the message is slightly modified to include an optional
|
|
topic at the start of the message. Note that in the HTTP API, all messages are encoded in base64. This
|
|
might make it difficult to consume these messages without additional tooling.
|
|
|
|
## Curl Examples
|
|
|
|
These examples assume you have at least 2 nodes running, and that they are both part of the same network.
|
|
|
|
Send a message on node1, waiting up to 2 minutes for a possible reply:
|
|
|
|
```bash
|
|
curl -v -H 'Content-Type: application/json' -d '{"dst": {"pk": "bb39b4a3a4efd70f3e05e37887677e02efbda14681d0acd3882bc0f754792c32"}, "payload": "xuV+"}' http://localhost:8989/api/v1/messages\?reply_timeout\=120
|
|
```
|
|
|
|
Listen for a message on node2. Note that messages received while nothing is listening are added to
|
|
a queue for later consumption. Wait for up to 1 minute.
|
|
|
|
```bash
|
|
curl -v http://localhost:8989/api/v1/messages\?timeout\=60\
|
|
```
|
|
|
|
The system will (immediately) receive our previously sent message:
|
|
|
|
```json
|
|
{"id":"e47b25063912f4a9","srcIp":"34f:b680:ba6e:7ced:355f:346f:d97b:eecb","srcPk":"955bf6bea5e1150fd8e270c12e5b2fc08f08f7c5f3799d10550096cc137d671b","dstIp":"2e4:9ace:9252:630:beee:e405:74c0:d876","dstPk":"bb39b4a3a4efd70f3e05e37887677e02efbda14681d0acd3882bc0f754792c32","payload":"xuV+"}
|
|
```
|
|
|
|
To send a reply, we can post a message on the reply path, with the received message `id` (still on
|
|
node2):
|
|
|
|
```bash
|
|
curl -H 'Content-Type: application/json' -d '{"dst": {"pk":"955bf6bea5e1150fd8e270c12e5b2fc08f08f7c5f3799d10550096cc137d671b"}, "payload": "xuC+"}' http://localhost:8989/api/v1/messages/reply/e47b25063912f4a9
|
|
```
|
|
|
|
If you did this fast enough, the initial sender (node1) will now receive the reply.
|
|
|
|
## Mycelium Binary Examples
|
|
|
|
As explained above, while using the binary the message is slightly modified to insert the optional
|
|
topic. As such, when using the binary to send messages, it is suggested to make sure the receiver is
|
|
also using the binary to listen for messages. The options discussed here are not covering all possibilities,
|
|
use the `--help` flag (`mycelium message send --help` and `mycelium message receive --help`) for a
|
|
full overview.
|
|
|
|
Once again, send a message. This time using a topic (example.topic). Note that there are no constraints
|
|
on what a valid topic is, other than that it is valid UTF-8, and at most 255 bytes in size. The `--wait`
|
|
flag can be used to indicate that we are waiting for a reply. If it is set, we can also use an additional
|
|
`--timeout` flag to govern exactly how long (in seconds) to wait for. The default is to wait forever.
|
|
|
|
```bash
|
|
mycelium message send 2e4:9ace:9252:630:beee:e405:74c0:d876 'this is a message' -t example.topic --wait
|
|
```
|
|
|
|
On the second node, listen for messages with this topic. If a different topic is used, the previous
|
|
message won't be received. If no topic is set, all messages are received. An optional timeout flag
|
|
can be specified, which indicates how long to wait for. Absence of this flag will cause the binary
|
|
to wait forever.
|
|
|
|
```bash
|
|
mycelium message receive -t example.topic
|
|
```
|
|
|
|
Again, if the previous command was executed a message will be received immediately:
|
|
|
|
```json
|
|
{"id":"4a6c956e8d36381f","topic":"example.topic","srcIp":"34f:b680:ba6e:7ced:355f:346f:d97b:eecb","srcPk":"955bf6bea5e1150fd8e270c12e5b2fc08f08f7c5f3799d10550096cc137d671b","dstIp":"2e4:9ace:9252:630:beee:e405:74c0:d876","dstPk":"bb39b4a3a4efd70f3e05e37887677e02efbda14681d0acd3882bc0f754792c32","payload":"this is a message"}
|
|
```
|
|
|
|
And once again, we can use the ID from this message to reply to the original sender, who might be waiting
|
|
for this reply (notice we used the hex encoded public key to identify the receiver here, rather than an IP):
|
|
|
|
```bash
|
|
mycelium message send 955bf6bea5e1150fd8e270c12e5b2fc08f08f7c5f3799d10550096cc137d671b "this is a reply" --reply-to 4a6c956e8d36381f
|
|
```
|