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elasticsearch-js/docs/examples/asStream.asciidoc
2019-02-15 18:36:28 +01:00

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== asStream
Instead of getting the parsed body back, you will get the raw Node.js stream of data.
[source,js]
----
'use strict'
const { Client } = require('@elastic/elasticsearch')
const client = new Client({ node: 'http://localhost:9200' })
async function run () {
await client.bulk({
refresh: true,
body: [
// operation to perform
{ index: { _index: 'game-of-thrones' } },
// the document to index
{
character: 'Ned Stark',
quote: 'Winter is coming.'
},
{ index: { _index: 'game-of-thrones' } },
{
character: 'Daenerys Targaryen',
quote: 'I am the blood of the dragon.'
},
{ index: { _index: 'game-of-thrones' } },
{
character: 'Tyrion Lannister',
quote: 'A mind needs books like a sword needs a whetstone.'
}
]
})
// Let's search!
const { body } = await client.search({
index: 'game-of-thrones',
body: {
query: {
match: {
quote: 'winter'
}
}
}
}, {
asStream: true
})
// stream async iteration, available in Node.js ≥ 10
var payload = ''
body.setEncoding('utf8')
for await (const chunk of body) {
payload += chunk
}
console.log(JSON.parse(payload))
// classic stream callback style
var payload = ''
body.setEncoding('utf8')
body.on('data', chunk => { payload += chunk })
body.on('error', console.log)
body.on('end', () => {
console.log(JSON.parse(payload))
})
}
run().catch(console.log)
----
TIP: This can be useful if you need to pipe the Elasticsearch's response to a proxy, or send it directly to another source.
[source,js]
----
'use strict'
const { Client } = require('@elastic/elasticsearch')
const client = new Client({ node: 'http://localhost:9200' })
const fastify = require('fastify')()
fastify.post('/search/:index', async (req, reply) => {
const { body, statusCode, headers } = await client.search({
index: req.params.index,
body: req.body
}, {
asStream: true
})
reply.code(statusCode).headers(headers)
return body
})
fastify.listen(3000)
----