Files
shields/services/dynamic/dynamic-xml.service.js
2021-07-09 12:53:55 +01:00

80 lines
2.3 KiB
JavaScript

import { DOMParser } from 'xmldom'
import xpath from 'xpath'
import { MetricNames } from '../../core/base-service/metric-helper.js'
import { renderDynamicBadge, errorMessages } from '../dynamic-common.js'
import { BaseService, InvalidResponse, InvalidParameter } from '../index.js'
import { createRoute } from './dynamic-helpers.js'
// This service extends BaseService because it uses a different XML parser
// than BaseXmlService which can be used with xpath.
//
// One way to create a more performant version would be to use the BaseXml
// JSON parser and write the queries in jsonpath instead. Then eventually
// deprecate the old version.
export default class DynamicXml extends BaseService {
static category = 'dynamic'
static enabledMetrics = [MetricNames.SERVICE_RESPONSE_SIZE]
static route = createRoute('xml')
static defaultBadgeData = { label: 'custom badge' }
transform({ pathExpression, buffer }) {
// e.g. //book[2]/@id
const pathIsAttr = (
pathExpression.split('/').slice(-1)[0] || ''
).startsWith('@')
const parsed = new DOMParser().parseFromString(buffer)
let values
try {
values = xpath.select(pathExpression, parsed)
} catch (e) {
throw new InvalidParameter({ prettyMessage: e.message })
}
if (
typeof values === 'string' ||
typeof values === 'number' ||
typeof values === 'boolean'
) {
values = [values]
} else if (Array.isArray(values)) {
values = values.reduce((accum, node) => {
if (pathIsAttr) {
accum.push(node.value)
} else if (node.firstChild) {
accum.push(node.firstChild.data)
} else {
accum.push(node.data)
}
return accum
}, [])
} else {
throw new InvalidResponse({
prettyMessage: 'unsupported query',
})
}
if (!values.length) {
throw new InvalidResponse({ prettyMessage: 'no result' })
}
return { values }
}
async handle(_namedParams, { url, query: pathExpression, prefix, suffix }) {
const { buffer } = await this._request({
url,
options: { headers: { Accept: 'application/xml, text/xml' } },
errorMessages,
})
const { values: value } = this.transform({
pathExpression,
buffer,
})
return renderDynamicBadge({ value, prefix, suffix })
}
}