Mule ESB download file from URL string

问题

So, using Mule ESB, I'm searching Bing for certain PDF files. Then I'm parsing the JSON response to capture the URL of the file location. Now I need to retrieve the file and save locally. Below is what I have so far, but I have a feeling I'm going about this all wrong. How can I complete the use case?

I'm having two problems:

1) Can't figure out how to strip "http" from #[message.payload.Url] (since the HTTP Endpoint adds http to the url I'm passing in.

2) Can't figure out how to retrieve the file. I don't even know if HTTP Endpoint is the right option. HTTP? File?

<?xml version="1.0" encoding="UTF-8"?>

<mule xmlns:file="http://www.mulesoft.org/schema/mule/file" xmlns:http="http://www.mulesoft.org/schema/mule/http" xmlns:json="http://www.mulesoft.org/schema/mule/json" xmlns:https="http://www.mulesoft.org/schema/mule/https" xmlns="http://www.mulesoft.org/schema/mule/core" xmlns:doc="http://www.mulesoft.org/schema/mule/documentation" xmlns:spring="http://www.springframework.org/schema/beans" version="CE-3.3.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="
http://www.mulesoft.org/schema/mule/json http://www.mulesoft.org/schema/mule/json/current/mule-json.xsd 
http://www.mulesoft.org/schema/mule/http http://www.mulesoft.org/schema/mule/http/current/mule-http.xsd 
http://www.mulesoft.org/schema/mule/https http://www.mulesoft.org/schema/mule/https/current/mule-https.xsd 
http://www.mulesoft.org/schema/mule/file http://www.mulesoft.org/schema/mule/file/current/mule-file.xsd 
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-current.xsd 
http://www.mulesoft.org/schema/mule/core http://www.mulesoft.org/schema/mule/core/current/mule.xsd ">
    <flow name="BingFlow1" doc:name="BingFlow1">
        <http:inbound-endpoint exchange-pattern="request-response" host="localhost" port="8081" doc:name="HTTP"/>
        <https:outbound-endpoint exchange-pattern="request-response" host="api.datamarket.azure.com" port="443" path="Data.ashx/Bing/Search/v1/Web?Query=%27contract%20california%27&amp;WebFileType=%27PDF%27&amp;$top=50&amp;$format=Json" user="********" password="*****" doc:name="Bing"/>
        <json:json-to-object-transformer returnClass="java.util.Map" doc:name="JSON to Object"/>
        <expression-transformer expression="#[message.payload.d.results]" doc:name="Expression"/>
        <collection-splitter doc:name="Collection Splitter"/>
        <http:outbound-endpoint exchange-pattern="request-response" host="#[message.payload.Url]" port="80" method="GET" doc:name="HTTP"/>
        <file:outbound-endpoint path="/home/user/Documents/output" outputPattern="#[message.payload.ID].pdf" responseTimeout="10000" doc:name="File"/>
        <echo-component doc:name="Echo"/>
    </flow>
</mule>

回答1:

I couldn't test the flow because some credentials are needed but the following should help you:

• Use an expression-transformer to strip the HTTP out,
• Your approach with an http:outbound-endpoint followed by a file:outbound-endpoint will work fine,
• Change the http:inbound-endpoint to one-way: there is no way to return anything sensible since the execution flow gets split.

For example, assuming message.payload.Url resolves to a java.lang.String, you can use:

<expression-transformer expression="#[org.mule.util.StringUtils.substringAfter(message.payload.Url, 'http://')]" doc:name="Expression"/>

来源：https://stackoverflow.com/questions/12945051/mule-esb-download-file-from-url-string