Fix listen after reconnect - fixes #490

Author: porsager

cjs/src/index.js

@@ -171,16 +171,15 @@ function Postgres(a, b) {
 
     if (exists) {
       channels[name].listeners.push(listener)
+      const result = await channels[name].result
       listener.onlisten && listener.onlisten()
-      return Promise.resolve({ ...channels[name].result, unlisten })
+      return { state: result.state, unlisten }
     }
 
-    const result = await sql`listen ${ sql(name) }`
-    channels[name] = { result, listeners: [listener] }
+    channels[name] = { result: sql`listen ${ sql(name) }`, listeners: [listener] }
+    const result = await channels[name].result
     listener.onlisten && listener.onlisten()
-    result.unlisten = unlisten
-
-    return result
+    return { state: result.state, unlisten }
 
     async function unlisten() {
       if (name in channels === false)

cjs/tests/index.js

@@ -681,6 +681,23 @@ t('double listen', async() => {
   return [2, count]
 })
 
+t('multiple listeners work after a reconnect', async() => {
+  const sql = postgres(options)
+      , xs = []
+
+  const s1 = await sql.listen('test', x => xs.push('1', x))
+  await sql.listen('test', x => xs.push('2', x))
+  await sql.notify('test', 'a')
+  await delay(50)
+  await sql`select pg_terminate_backend(${ s1.state.pid })`
+  await delay(200)
+  await sql.notify('test', 'b')
+  await delay(50)
+  sql.end()
+
+  return ['1a2a1b2b', xs.join('')]
+})
+
 t('listen and notify with weird name', async() => {
   const sql = postgres(options)
   const channel = 'wat-;ø§'

deno/src/index.js

@@ -172,16 +172,15 @@ function Postgres(a, b) {
 
     if (exists) {
       channels[name].listeners.push(listener)
+      const result = await channels[name].result
       listener.onlisten && listener.onlisten()
-      return Promise.resolve({ ...channels[name].result, unlisten })
+      return { state: result.state, unlisten }
     }
 
-    const result = await sql`listen ${ sql(name) }`
-    channels[name] = { result, listeners: [listener] }
+    channels[name] = { result: sql`listen ${ sql(name) }`, listeners: [listener] }
+    const result = await channels[name].result
     listener.onlisten && listener.onlisten()
-    result.unlisten = unlisten
-
-    return result
+    return { state: result.state, unlisten }
 
     async function unlisten() {
       if (name in channels === false)

deno/tests/index.js

@@ -683,6 +683,23 @@ t('double listen', async() => {
   return [2, count]
 })
 
+t('multiple listeners work after a reconnect', async() => {
+  const sql = postgres(options)
+      , xs = []
+
+  const s1 = await sql.listen('test', x => xs.push('1', x))
+  await sql.listen('test', x => xs.push('2', x))
+  await sql.notify('test', 'a')
+  await delay(50)
+  await sql`select pg_terminate_backend(${ s1.state.pid })`
+  await delay(200)
+  await sql.notify('test', 'b')
+  await delay(50)
+  sql.end()
+
+  return ['1a2a1b2b', xs.join('')]
+})
+
 t('listen and notify with weird name', async() => {
   const sql = postgres(options)
   const channel = 'wat-;ø§'

src/index.js

@@ -171,16 +171,15 @@ function Postgres(a, b) {
 
     if (exists) {
       channels[name].listeners.push(listener)
+      const result = await channels[name].result
       listener.onlisten && listener.onlisten()
-      return Promise.resolve({ ...channels[name].result, unlisten })
+      return { state: result.state, unlisten }
     }
 
-    const result = await sql`listen ${ sql(name) }`
-    channels[name] = { result, listeners: [listener] }
+    channels[name] = { result: sql`listen ${ sql(name) }`, listeners: [listener] }
+    const result = await channels[name].result
     listener.onlisten && listener.onlisten()
-    result.unlisten = unlisten
-
-    return result
+    return { state: result.state, unlisten }
 
     async function unlisten() {
       if (name in channels === false)

tests/index.js

@@ -681,6 +681,23 @@ t('double listen', async() => {
   return [2, count]
 })
 
+t('multiple listeners work after a reconnect', async() => {
+  const sql = postgres(options)
+      , xs = []
+
+  const s1 = await sql.listen('test', x => xs.push('1', x))
+  await sql.listen('test', x => xs.push('2', x))
+  await sql.notify('test', 'a')
+  await delay(50)
+  await sql`select pg_terminate_backend(${ s1.state.pid })`
+  await delay(200)
+  await sql.notify('test', 'b')
+  await delay(50)
+  sql.end()
+
+  return ['1a2a1b2b', xs.join('')]
+})
+
 t('listen and notify with weird name', async() => {
   const sql = postgres(options)
   const channel = 'wat-;ø§'