使用 WSO2 ESB 组合两个查询
Combine two queries using WSO2 ESB
我一直在想办法让 WSO2 的 ESB 调用两个不同的 APIs 并将它们的结果组合成一个响应，而 运行 只会带来麻烦。在最基本的情况下，我有两个后端，我正在向它们发出请求，响应如下：
<?xml version="1.0" encoding="UTF-8"?>
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<soapenv:Body>
<response xmlns="http://example.com/response">
<query name="items" xmlns="http://example.com/query">
<row>
<id>1</id>
<name>Item 1</name>
</row>
<row>
<id>2</id>
<name>Item 2</name>
</row>
</query>
</response>
</soapenv:Body>
</soapenv:Envelope>
<?xml version="1.0" encoding="UTF-8"?>
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<soapenv:Body>
<response xmlns="http://example.com/response">
<query name="parts" xmlns="http://example.com/query">
<row>
<id>1</id>
<part>Part 1.1</part>
</row>
<row>
<id>1</id>
<part>Part 1.2</part>
</row>
<row>
<id>1</id>
<part>Part 1.3</part>
</row>
<row>
<id>2</id>
<part>Part 2.1</part>
</row>
<row>
<id>2</id>
<part>Part 2.2</part>
</row>
</query>
</response>
</soapenv:Body>
</soapenv:Envelope>
我想请求这两个，然后将它们的结果组合起来如下所示：
<items>
<item>
<id>1</id>
<name>Item 1</name>
<parts>
<part>
<id>1</id>
<name>Part 1.1</name>
</part>
<part>
<id>1</id>
<name>Part 1.2</name>
</part>
<part>
<id>1</id>
<name>Part 1.3</name>
</part>
</parts>
</item>
<item>
<id>2</id>
<name>Item 2</name>
<parts>
<part>
<id>2</id>
<name>Part 2.1</name>
</part>
<part>
<id>2</id>
<name>Part 2.2</name>
</part>
</parts>
</item>
</items>
基本上，来自两个 API 的每个响应都有一个 row 的列表，每个列表都包含一个 id 元素。对 /items 的调用中的 id 在该响应中是唯一的，并且来自 parts 的响应中的每一行都有一个 id 将其与来自 [= 的行联系起来17=].
我在 ESB 中有以下 API 定义：
<?xml version="1.0" encoding="UTF-8"?>
<api context="/item_list" name="ItemList" xmlns="http://ws.apache.org/ns/synapse">
<resource methods="POST" uri-template="/">
<inSequence>
<header name="Content-Type" scope="transport" value="text/xml; charset=utf-8"/>
<clone>
<target>
<sequence>
<send>
<endpoint>
<address format="soap11" uri="http://example.com/items"/>
</endpoint>
</send>
</sequence>
</target>
<target>
<sequence>
<send>
<endpoint>
<address format="soap11" uri="http://example.com/parts"/>
</endpoint>
</send>
</sequence>
</target>
</clone>
</inSequence>
<outSequence>
<aggregate>
<correlateOn expression="//*[name()='response']/*[name()='query']/*[name()='row']/*[name()='id']" />
<completeCondition>
<messageCount max="2" min="2"/>
</completeCondition>
<onComplete expression="//*[name()='response']/*[name()='query']/*[name()='row']">
<send/>
</onComplete>
</aggregate>
</outSequence>
<faultSequence/>
</resource>
</api>
此处的 inSequence 已大大简化，但它确实发送了两个有效查询并返回了预期的响应。此处编写的 outSequence 从不向客户端发送响应或在服务器上记录错误。如果我从 aggregate 中删除 correlateOn 元素，我会从两个 API 调用之一中随机取回一个 row。我 认为 correlateOn 是我想在这里使用的东西，但我无法从 WSO2 或 Apache 找到任何有用的文档，所以我确定我'我使用不当。我的 XPath 背景很薄弱，所以我相信表达式也可以使用一些工作。
我至少在 clone/aggregate 模式的正确轨道上吗？我将如何将这两个查询的结果组合成类似于我的示例的结果？如果我能得到一些接近的东西，我应该能够用 XSLT 完成剩下的工作。
看看这个演示：
具有项目响应的后端 1：
<?xml version="1.0" encoding="UTF-8"?>
<proxy xmlns="http://ws.apache.org/ns/synapse"
name="items"
transports="https http"
startOnLoad="true">
<target>
<inSequence>
<payloadFactory media-type="xml">
<format>
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<soapenv:Body>
<response xmlns="http://example.com/response">
<query xmlns="http://example.com/query" name="items">
<row>
<id>1</id>
<name>Item 1</name>
</row>
<row>
<id>2</id>
<name>Item 2</name>
</row>
</query>
</response>
</soapenv:Body>
</soapenv:Envelope>
</format>
<args/>
</payloadFactory>
<log level="full"/>
<loopback/>
</inSequence>
<outSequence>
<send/>
</outSequence>
<faultSequence/>
</target>
</proxy>
具有部件响应的后端 2：
<?xml version="1.0" encoding="UTF-8"?>
<proxy xmlns="http://ws.apache.org/ns/synapse"
name="parts"
transports="https http"
startOnLoad="true">
<target>
<inSequence>
<payloadFactory media-type="xml">
<format>
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<soapenv:Body>
<response xmlns="http://example.com/response">
<query xmlns="http://example.com/query" name="parts">
<row>
<id>1</id>
<part>Part 1.1</part>
</row>
<row>
<id>1</id>
<part>Part 1.2</part>
</row>
<row>
<id>1</id>
<part>Part 1.3</part>
</row>
<row>
<id>2</id>
<part>Part 2.1</part>
</row>
<row>
<id>2</id>
<part>Part 2.2</part>
</row>
</query>
</response>
</soapenv:Body>
</soapenv:Envelope>
</format>
<args/>
</payloadFactory>
<log level="full"/>
<loopback/>
</inSequence>
<outSequence>
<send/>
</outSequence>
<faultSequence/>
</target>
</proxy>
我的 API 调用后端 1 和后端 2 并使用 xslt 进行转换：
<?xml version="1.0" encoding="UTF-8"?>
<api xmlns="http://ws.apache.org/ns/synapse"
name="ItemList"
context="/item_list">
<resource methods="POST" uri-template="/">
<inSequence>
<header name="Action" scope="default" value="urn:mediate"/>
<call>
<endpoint>
<address uri="http://localhost:8283/services/items.itemsHttpSoap11Endpoint"
format="soap11"/>
</endpoint>
</call>
<enrich>
<source type="inline" clone="true">
<Payloads/>
</source>
<target type="property" property="Items"/>
</enrich>
<enrich>
<source clone="true" xpath="$body/*"/>
<target action="child" xpath="$ctx:Items"/>
</enrich>
<payloadFactory media-type="xml">
<format>
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<soapenv:Body/>
</soapenv:Envelope>
</format>
<args/>
</payloadFactory>
<call>
<endpoint>
<address uri="http://localhost:8283/services/parts.partsHttpSoap11Endpoint"
format="soap11"/>
</endpoint>
</call>
<enrich>
<source clone="true" xpath="$body/*[name()='response']/*[name()='query']"/>
<target type="property" property="Parts"/>
</enrich>
<enrich>
<source type="property" clone="true" property="Parts"/>
<target action="child" xpath="$ctx:Items"/>
</enrich>
<enrich>
<source type="property" property="Items"/>
<target type="body"/>
</enrich>
<xslt key="transformTwoSourcesToOneResult"/>
<loopback/>
</inSequence>
<outSequence>
<send/>
</outSequence>
<faultSequence/>
</resource>
</api>
我的 xslt 转换：
<?xml version="1.0" encoding="UTF-8"?>
<localEntry key="transformTwoSourcesToOneResult" xmlns="http://ws.apache.org/ns/synapse">
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:ns0="http://example.com/query"
xmlns:ns1="http://example.com/response"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:exslt="http://exslt.org/common"
xmlns:saxon="http://saxon.sf.net/"
xmlns:syn="http://ws.apache.org/ns/synapse"
exclude-result-prefixes="ns0 ns1 xs">
<xsl:output method="xml" encoding="UTF-8" indent="yes"/>
<xsl:template match="/">
<xsl:variable name="var1_instance_Payloads" select="."/>
<items>
<xsl:for-each select="$var1_instance_Payloads/syn:Payloads">
<xsl:variable name="var2_Payloads" select="."/>
<xsl:for-each select="$var2_Payloads/ns1:response/ns0:query/ns0:row">
<xsl:variable name="var2_row" select="."/>
<item>
<id>
<xsl:value-of select="number(string($var2_row/ns0:id))"/>
</id>
<name>
<xsl:value-of select="string($var2_row/ns0:name)"/>
</name>
<parts>
<xsl:for-each select="$var2_Payloads/ns0:query/ns0:row">
<xsl:variable name="var4_row" select="."/>
<xsl:if test="string((number(string($var2_row/ns0:id)) = number(string($var4_row/ns0:id)))) != 'false'">
<part>
<id>
<xsl:value-of select="number(string($var4_row/ns0:id))"/>
</id>
<name>
<xsl:value-of select="string($var4_row/ns0:part)"/>
</name>
</part>
</xsl:if>
</xsl:for-each>
</parts>
</item>
</xsl:for-each>
</xsl:for-each>
</items>
</xsl:template>
</xsl:stylesheet>
</localEntry>
API 响应：
<items xmlns="http://ws.apache.org/ns/synapse" xmlns:syn="http://ws.apache.org/ns/synapse" xmlns:saxon="http://saxon.sf.net/" xmlns:exslt="http://exslt.org/common">
<item>
<id>1</id>
<name>Item 1</name>
<parts>
<part>
<id>1</id>
<name>Part 1.1</name>
</part>
<part>
<id>1</id>
<name>Part 1.2</name>
</part>
<part>
<id>1</id>
<name>Part 1.3</name>
</part>
</parts>
</item>
<item>
<id>2</id>
<name>Item 2</name>
<parts>
<part>
<id>2</id>
<name>Part 2.1</name>
</part>
<part>
<id>2</id>
<name>Part 2.2</name>
</part>
</parts>
</item>
</items>
我一直在想办法让 WSO2 的 ESB 调用两个不同的 APIs 并将它们的结果组合成一个响应，而 运行 只会带来麻烦。在最基本的情况下，我有两个后端，我正在向它们发出请求，响应如下：
<?xml version="1.0" encoding="UTF-8"?>
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<soapenv:Body>
<response xmlns="http://example.com/response">
<query name="items" xmlns="http://example.com/query">
<row>
<id>1</id>
<name>Item 1</name>
</row>
<row>
<id>2</id>
<name>Item 2</name>
</row>
</query>
</response>
</soapenv:Body>
</soapenv:Envelope>
<?xml version="1.0" encoding="UTF-8"?>
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<soapenv:Body>
<response xmlns="http://example.com/response">
<query name="parts" xmlns="http://example.com/query">
<row>
<id>1</id>
<part>Part 1.1</part>
</row>
<row>
<id>1</id>
<part>Part 1.2</part>
</row>
<row>
<id>1</id>
<part>Part 1.3</part>
</row>
<row>
<id>2</id>
<part>Part 2.1</part>
</row>
<row>
<id>2</id>
<part>Part 2.2</part>
</row>
</query>
</response>
</soapenv:Body>
</soapenv:Envelope>
我想请求这两个，然后将它们的结果组合起来如下所示：
<items>
<item>
<id>1</id>
<name>Item 1</name>
<parts>
<part>
<id>1</id>
<name>Part 1.1</name>
</part>
<part>
<id>1</id>
<name>Part 1.2</name>
</part>
<part>
<id>1</id>
<name>Part 1.3</name>
</part>
</parts>
</item>
<item>
<id>2</id>
<name>Item 2</name>
<parts>
<part>
<id>2</id>
<name>Part 2.1</name>
</part>
<part>
<id>2</id>
<name>Part 2.2</name>
</part>
</parts>
</item>
</items>
基本上，来自两个 API 的每个响应都有一个 row 的列表，每个列表都包含一个 id 元素。对 /items 的调用中的 id 在该响应中是唯一的，并且来自 parts 的响应中的每一行都有一个 id 将其与来自 [= 的行联系起来17=].
我在 ESB 中有以下 API 定义：
<?xml version="1.0" encoding="UTF-8"?>
<api context="/item_list" name="ItemList" xmlns="http://ws.apache.org/ns/synapse">
<resource methods="POST" uri-template="/">
<inSequence>
<header name="Content-Type" scope="transport" value="text/xml; charset=utf-8"/>
<clone>
<target>
<sequence>
<send>
<endpoint>
<address format="soap11" uri="http://example.com/items"/>
</endpoint>
</send>
</sequence>
</target>
<target>
<sequence>
<send>
<endpoint>
<address format="soap11" uri="http://example.com/parts"/>
</endpoint>
</send>
</sequence>
</target>
</clone>
</inSequence>
<outSequence>
<aggregate>
<correlateOn expression="//*[name()='response']/*[name()='query']/*[name()='row']/*[name()='id']" />
<completeCondition>
<messageCount max="2" min="2"/>
</completeCondition>
<onComplete expression="//*[name()='response']/*[name()='query']/*[name()='row']">
<send/>
</onComplete>
</aggregate>
</outSequence>
<faultSequence/>
</resource>
</api>
此处的 inSequence 已大大简化，但它确实发送了两个有效查询并返回了预期的响应。此处编写的 outSequence 从不向客户端发送响应或在服务器上记录错误。如果我从 aggregate 中删除 correlateOn 元素，我会从两个 API 调用之一中随机取回一个 row。我 认为 correlateOn 是我想在这里使用的东西，但我无法从 WSO2 或 Apache 找到任何有用的文档，所以我确定我'我使用不当。我的 XPath 背景很薄弱，所以我相信表达式也可以使用一些工作。
我至少在 clone/aggregate 模式的正确轨道上吗？我将如何将这两个查询的结果组合成类似于我的示例的结果？如果我能得到一些接近的东西，我应该能够用 XSLT 完成剩下的工作。
看看这个演示：
具有项目响应的后端 1：
<?xml version="1.0" encoding="UTF-8"?>
<proxy xmlns="http://ws.apache.org/ns/synapse"
name="items"
transports="https http"
startOnLoad="true">
<target>
<inSequence>
<payloadFactory media-type="xml">
<format>
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<soapenv:Body>
<response xmlns="http://example.com/response">
<query xmlns="http://example.com/query" name="items">
<row>
<id>1</id>
<name>Item 1</name>
</row>
<row>
<id>2</id>
<name>Item 2</name>
</row>
</query>
</response>
</soapenv:Body>
</soapenv:Envelope>
</format>
<args/>
</payloadFactory>
<log level="full"/>
<loopback/>
</inSequence>
<outSequence>
<send/>
</outSequence>
<faultSequence/>
</target>
</proxy>
具有部件响应的后端 2：
<?xml version="1.0" encoding="UTF-8"?>
<proxy xmlns="http://ws.apache.org/ns/synapse"
name="parts"
transports="https http"
startOnLoad="true">
<target>
<inSequence>
<payloadFactory media-type="xml">
<format>
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<soapenv:Body>
<response xmlns="http://example.com/response">
<query xmlns="http://example.com/query" name="parts">
<row>
<id>1</id>
<part>Part 1.1</part>
</row>
<row>
<id>1</id>
<part>Part 1.2</part>
</row>
<row>
<id>1</id>
<part>Part 1.3</part>
</row>
<row>
<id>2</id>
<part>Part 2.1</part>
</row>
<row>
<id>2</id>
<part>Part 2.2</part>
</row>
</query>
</response>
</soapenv:Body>
</soapenv:Envelope>
</format>
<args/>
</payloadFactory>
<log level="full"/>
<loopback/>
</inSequence>
<outSequence>
<send/>
</outSequence>
<faultSequence/>
</target>
</proxy>
我的 API 调用后端 1 和后端 2 并使用 xslt 进行转换：
<?xml version="1.0" encoding="UTF-8"?>
<api xmlns="http://ws.apache.org/ns/synapse"
name="ItemList"
context="/item_list">
<resource methods="POST" uri-template="/">
<inSequence>
<header name="Action" scope="default" value="urn:mediate"/>
<call>
<endpoint>
<address uri="http://localhost:8283/services/items.itemsHttpSoap11Endpoint"
format="soap11"/>
</endpoint>
</call>
<enrich>
<source type="inline" clone="true">
<Payloads/>
</source>
<target type="property" property="Items"/>
</enrich>
<enrich>
<source clone="true" xpath="$body/*"/>
<target action="child" xpath="$ctx:Items"/>
</enrich>
<payloadFactory media-type="xml">
<format>
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<soapenv:Body/>
</soapenv:Envelope>
</format>
<args/>
</payloadFactory>
<call>
<endpoint>
<address uri="http://localhost:8283/services/parts.partsHttpSoap11Endpoint"
format="soap11"/>
</endpoint>
</call>
<enrich>
<source clone="true" xpath="$body/*[name()='response']/*[name()='query']"/>
<target type="property" property="Parts"/>
</enrich>
<enrich>
<source type="property" clone="true" property="Parts"/>
<target action="child" xpath="$ctx:Items"/>
</enrich>
<enrich>
<source type="property" property="Items"/>
<target type="body"/>
</enrich>
<xslt key="transformTwoSourcesToOneResult"/>
<loopback/>
</inSequence>
<outSequence>
<send/>
</outSequence>
<faultSequence/>
</resource>
</api>
我的 xslt 转换：
<?xml version="1.0" encoding="UTF-8"?>
<localEntry key="transformTwoSourcesToOneResult" xmlns="http://ws.apache.org/ns/synapse">
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:ns0="http://example.com/query"
xmlns:ns1="http://example.com/response"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:exslt="http://exslt.org/common"
xmlns:saxon="http://saxon.sf.net/"
xmlns:syn="http://ws.apache.org/ns/synapse"
exclude-result-prefixes="ns0 ns1 xs">
<xsl:output method="xml" encoding="UTF-8" indent="yes"/>
<xsl:template match="/">
<xsl:variable name="var1_instance_Payloads" select="."/>
<items>
<xsl:for-each select="$var1_instance_Payloads/syn:Payloads">
<xsl:variable name="var2_Payloads" select="."/>
<xsl:for-each select="$var2_Payloads/ns1:response/ns0:query/ns0:row">
<xsl:variable name="var2_row" select="."/>
<item>
<id>
<xsl:value-of select="number(string($var2_row/ns0:id))"/>
</id>
<name>
<xsl:value-of select="string($var2_row/ns0:name)"/>
</name>
<parts>
<xsl:for-each select="$var2_Payloads/ns0:query/ns0:row">
<xsl:variable name="var4_row" select="."/>
<xsl:if test="string((number(string($var2_row/ns0:id)) = number(string($var4_row/ns0:id)))) != 'false'">
<part>
<id>
<xsl:value-of select="number(string($var4_row/ns0:id))"/>
</id>
<name>
<xsl:value-of select="string($var4_row/ns0:part)"/>
</name>
</part>
</xsl:if>
</xsl:for-each>
</parts>
</item>
</xsl:for-each>
</xsl:for-each>
</items>
</xsl:template>
</xsl:stylesheet>
</localEntry>
API 响应：
<items xmlns="http://ws.apache.org/ns/synapse" xmlns:syn="http://ws.apache.org/ns/synapse" xmlns:saxon="http://saxon.sf.net/" xmlns:exslt="http://exslt.org/common">
<item>
<id>1</id>
<name>Item 1</name>
<parts>
<part>
<id>1</id>
<name>Part 1.1</name>
</part>
<part>
<id>1</id>
<name>Part 1.2</name>
</part>
<part>
<id>1</id>
<name>Part 1.3</name>
</part>
</parts>
</item>
<item>
<id>2</id>
<name>Item 2</name>
<parts>
<part>
<id>2</id>
<name>Part 2.1</name>
</part>
<part>
<id>2</id>
<name>Part 2.2</name>
</part>
</parts>
</item>
</items>