omnia_wasi_messaging/host/
resource.rs

1use std::any::Any;
2use std::collections::HashMap;
3use std::fmt::Debug;
4use std::ops::{Deref, DerefMut};
5use std::pin::Pin;
6use std::sync::Arc;
7
8use futures::Stream;
9pub use omnia::FutureResult;
10use serde::{Deserialize, Serialize};
11
12use crate::host::generated::wasi::messaging::types;
13/// Stream of message proxies.
14pub type Subscriptions = Pin<Box<dyn Stream<Item = MessageProxy> + Send>>;
15
16/// Messaging client trait.
17#[allow(unused_variables)]
18pub trait Client: Debug + Send + Sync + 'static {
19    /// Subscribe to messages.
20    fn subscribe(&self) -> FutureResult<Subscriptions>;
21
22    /// Send a message to a topic.
23    fn send(&self, topic: String, message: MessageProxy) -> FutureResult<()>;
24
25    /// Request a response from a topic.
26    fn request(
27        &self, topic: String, message: MessageProxy, options: Option<RequestOptions>,
28    ) -> FutureResult<MessageProxy>;
29}
30
31/// Proxy for a messaging client.
32#[derive(Clone, Debug)]
33pub struct ClientProxy(pub Arc<dyn Client>);
34
35impl Deref for ClientProxy {
36    type Target = Arc<dyn Client>;
37
38    fn deref(&self) -> &Self::Target {
39        &self.0
40    }
41}
42
43/// Providers implement the [`Message`] trait to allow the host to interact with
44/// different backend messaging systems.
45pub trait Message: Debug + Send + Sync + 'static {
46    /// Topic the message is published to.
47    fn topic(&self) -> String;
48
49    /// Message content.
50    fn payload(&self) -> Vec<u8>;
51
52    /// Headers or metadata associated with the message.
53    fn metadata(&self) -> Option<Metadata>;
54
55    /// Optional message description.
56    fn description(&self) -> Option<String>;
57
58    /// Number of bytes in the payload.
59    fn length(&self) -> usize;
60
61    /// Optional reply topic to which a response can be published.
62    fn reply(&self) -> Option<Reply>;
63
64    /// For downcasting support.
65    fn as_any(&self) -> &dyn Any;
66}
67
68/// Proxy for a message.
69#[derive(Clone, Debug)]
70pub struct MessageProxy(pub Arc<dyn Message>);
71
72impl Deref for MessageProxy {
73    type Target = Arc<dyn Message>;
74
75    fn deref(&self) -> &Self::Target {
76        &self.0
77    }
78}
79
80impl DerefMut for MessageProxy {
81    fn deref_mut(&mut self) -> &mut Self::Target {
82        &mut self.0
83    }
84}
85
86/// Metadata associated with a message.
87#[derive(Clone, Debug, Default, Deserialize, Serialize)]
88pub struct Metadata {
89    /// The metadata fields.
90    pub inner: HashMap<String, String>,
91}
92
93impl Metadata {
94    /// Create a new empty metadata object.
95    #[must_use]
96    pub fn new() -> Self {
97        Self {
98            inner: HashMap::new(),
99        }
100    }
101}
102
103impl Deref for Metadata {
104    type Target = HashMap<String, String>;
105
106    fn deref(&self) -> &Self::Target {
107        &self.inner
108    }
109}
110
111impl DerefMut for Metadata {
112    fn deref_mut(&mut self) -> &mut Self::Target {
113        &mut self.inner
114    }
115}
116
117impl From<Metadata> for types::Metadata {
118    fn from(meta: Metadata) -> Self {
119        let mut metadata = Self::new();
120        for (k, v) in meta.inner {
121            metadata.push((k, v));
122        }
123        metadata
124    }
125}
126
127impl From<types::Metadata> for Metadata {
128    fn from(meta: types::Metadata) -> Self {
129        let mut map = HashMap::new();
130        for (k, v) in meta {
131            map.insert(k, v);
132        }
133        Self { inner: map }
134    }
135}
136
137/// Reply information for a message.
138#[derive(Clone, Debug, Default, Deserialize, Serialize)]
139pub struct Reply {
140    /// The client name.
141    pub client_name: String,
142    /// The reply topic.
143    pub topic: String,
144}
145
146/// Options for messaging requests.
147#[derive(Default, Clone)]
148pub struct RequestOptions {
149    /// Request timeout.
150    pub timeout: Option<std::time::Duration>,
151    /// Number of expected replies.
152    pub expected_replies: Option<u32>,
153}
omnia_wasi_messaging/host/resource.rs

omnia_wasi_messaging/host/
resource.rs
