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|
use std::collections::HashMap;
use clock::Timestamp;
use serde::{Deserialize, Serialize};
use serde_json::Value;
use self::error::ThinEdgeJsonDeserializerError;
/// In-memory representation of ThinEdge JSON event.
#[derive(Debug, Serialize, Deserialize, Eq, PartialEq)]
pub struct ThinEdgeEvent {
#[serde(rename = "type")]
pub name: String,
#[serde(flatten)]
pub data: Option<ThinEdgeEventData>,
pub source: Option<String>,
}
/// In-memory representation of ThinEdge JSON event payload
#[derive(Debug, Serialize, Deserialize, Eq, PartialEq)]
pub struct ThinEdgeEventData {
pub text: Option<String>,
#[serde(default)]
#[serde(with = "time::serde::rfc3339::option")]
pub time: Option<Timestamp>,
#[serde(flatten)]
pub extras: HashMap<String, Value>,
}
pub mod error {
#[derive(thiserror::Error, Debug)]
pub enum ThinEdgeJsonDeserializerError {
#[error("Unsupported topic: {0}")]
UnsupportedTopic(String),
#[error("Event name can not be empty")]
EmptyEventName,
#[error(transparent)]
SerdeJsonError(#[from] serde_json::error::Error),
}
}
impl ThinEdgeEvent {
pub fn try_from(
mqtt_topic: &str,
mqtt_payload: &str,
) -> Result<Self, ThinEdgeJsonDeserializerError> {
let topic_split: Vec<&str> = mqtt_topic.split('/').collect();
if topic_split.len() == 3 || topic_split.len() == 4 {
let event_name = topic_split[2];
if event_name.is_empty() {
return Err(ThinEdgeJsonDeserializerError::EmptyEventName);
}
let event_data = if mqtt_payload.is_empty() {
None
} else {
Some(serde_json::from_str(mqtt_payload)?)
};
// The 4th part of the topic name is the event source - if any
let external_source = if topic_split.len() == 4 {
Some(topic_split[3].to_string())
} else {
None
};
Ok(Self {
name: event_name.into(),
data: event_data,
source: external_source,
})
} else {
Err(ThinEdgeJsonDeserializerError::UnsupportedTopic(
mqtt_topic.into(),
))
}
}
}
#[cfg(test)]
mod tests {
use super::*;
use anyhow::Result;
use assert_matches::assert_matches;
use serde_json::{json, Value};
use test_case::test_case;
use time::macros::datetime;
#[test_case(
"tedge/events/click_event",
json!({
"text": "Someone clicked",
"time": "2021-04-23T19:00:00+05:00",
}),
ThinEdgeEvent {
name: "click_event".into(),
data: Some(ThinEdgeEventData {
text: Some("Someone clicked".into()),
time: Some(datetime!(2021-04-23 19:00:00 +05:00)),
extras: HashMap::new(),
}),
source: None,
};
"event parsing"
)]
#[test_case(
"tedge/events/click_event",
json!({
"text": "Someone clicked",
}),
ThinEdgeEvent {
name: "click_event".into(),
data: Some(ThinEdgeEventData {
text: Some("Someone clicked".into()),
time: None,
extras: HashMap::new(),
}),
source: None,
};
"event parsing without timestamp"
)]
#[test_case(
"tedge/events/click_event",
json!({
"time": "2021-04-23T19:00:00+05:00",
}),
ThinEdgeEvent {
name: "click_event".into(),
data: Some(ThinEdgeEventData {
text: None,
time: Some(datetime!(2021-04-23 19:00:00 +05:00)),
extras: HashMap::new(),
}),
source: None,
};
"event parsing without text"
)]
#[test_case(
"tedge/events/click_event",
json!({}),
ThinEdgeEvent {
name: "click_event".into(),
data: Some(ThinEdgeEventData {
text: None,
time: None,
extras: HashMap::new(),
}),
source: None,
};
"event parsing without text or timestamp"
)]
#[test_case(
"tedge/events/click_event/external_source",
json!({
"text": "Someone clicked",
"time": "2021-04-23T19:00:00+05:00",
}),
ThinEdgeEvent {
name: "click_event".into(),
data: Some(ThinEdgeEventData {
text: Some("Someone clicked".into()),
time: Some(datetime!(2021-04-23 19:00:00 +05:00)),
extras: HashMap::new(),
}),
source: Some("external_source".into()),
};
"event parsing with external source"
)]
#[test_case(
"tedge/events/click_event/external_source",
json!({}),
ThinEdgeEvent {
name: "click_event".into(),
data: Some(ThinEdgeEventData {
text: None,
time: None,
extras: HashMap::new(),
}),
source: Some("external_source".into()),
};
"event parsing empty payload with external source"
)]
fn parse_thin_edge_event_json(
event_topic: &str,
event_payload: Value,
expected_event: ThinEdgeEvent,
) {
let event =
ThinEdgeEvent::try_from(event_topic, event_payload.to_string().as_str()).unwrap();
assert_eq!(event, expected_event);
}
#[test]
fn event_translation_empty_event_name() {
let result = ThinEdgeEvent::try_from("tedge/events/", "{}");
assert_matches!(result, Err(ThinEdgeJsonDeserializerError::EmptyEventName));
}
#[test]
fn event_translation_more_than_four_topic_levels() {
let result = ThinEdgeEvent::try_from("tedge/events/page/click/click", "{}");
assert_matches!(
result,
Err(ThinEdgeJsonDeserializerError::UnsupportedTopic(_))
);
}
#[test]
fn event_translation_empty_payload() -> Result<()> {
let event_data = ThinEdgeEventData {
text: Some("foo".to_string()),
time: Some(datetime!(2021-04-23 19:00:00 +05:00)),
extras: HashMap::new(),
};
let serialized = serde_json::to_string(&event_data).unwrap();
println!("serialized = {}", serialized);
Ok(())
}
#[test]
fn test_serialize() -> Result<()> {
let result = ThinEdgeEvent::try_from("tedge/events/click_event", "")?;
assert_eq!(result.name, "click_event".to_string());
assert_matches!(result.data, None);
Ok(())
}
#[test]
fn event_translation_additional_fields() -> Result<()> {
let event_json = json!({
"text": "foo",
"time": "2021-04-23T19:00:00+05:00",
"extra": "field",
"numeric": 32u64,
"complex": {
"hello": "world",
"num": 5u32
}
});
let result =
ThinEdgeEvent::try_from("tedge/events/click_event", event_json.to_string().as_str())?;
assert_eq!(result.name, "click_event".to_string());
let event_data = result.data.unwrap();
assert_eq!(
event_data.extras.get("extra").unwrap().as_str().unwrap(),
"field"
);
assert_eq!(
event_data.extras.get("numeric").unwrap().as_u64().unwrap(),
32u64
);
assert_matches!(event_data.extras.get("complex"), Some(Value::Object(_)));
Ok(())
}
}
|
