I coulnd't find any indication in Spring documentation that it support read of files in streaming mode in its object MultipartHttpServletRequest that handle multipart requests.
in similar way that is possible in Apache Commons framework.
is it supported in Spring at all?
Yes, have a look here. Your Spring API is far too old. Also, the Streaming mode has nothing to do with Spring. It is the ability of your servlet container or your server. Most server now support the streaming mode. Servlet will start performing the request as soon as it got the header from your request. You can continue to send out the stream of your request body (e.g. multipart data). However, the parsing can only be performed completely when the request is sent fully. This is the same as Apache Common FileUpload.
Alternatively, you can write a controller using Spring annotation. Spring will inject the ServletRequest if you add that as one of your method controller arugument. After that, you can use Apache FileUpload to do multipart parsing.
You can not do selective parsing since the request must be fully sent to server no matter what. It is the limit of Http. I asked the question a few day ago.
Related
I need to create a REST service that first consumes SOAP. What would the best way to go about this?
I would like to use Spring Boot to create a microservice, but I have a few questions for those with experience:
What other architectures or technologies should I look into using
(with spring boot)?
Is there a standard technology stack for this?
Are there pitfalls I should be aware of?
What other architectures or technologies should I look into using (with spring boot)?
My answer is if you just want to simply provide RESTful service
without Spring Cloud, then I think you can refer to following 2
tutorials on Spring official website to achieve this:
Building a RESTful Web Service
Consuming a SOAP web service
Is there a standard technology stack for this?
Currently, I will suggest you to use Spring Boot as your first choice. Because these are rich resources on the web and it does reduces much effort in development.
Are there pitfalls I should be aware of?
If you finally choose Spring Boot, please be familiar to its components, you can start from Guides to realize how it works. Or you may mix up Spring Boot with tradition Spring framework.
There are similar cases in our project and we did it with spring components. As far as i understood, you want to open a REST endpoint which most probably accepts json object and you want to make a soap web service request within that request then you want to return a response containing information from the soap response. To make a soap request, you can use spring web services - WebServiceTemplate. It will marshall your object to xml and make soap request for you. Of course you can use some other web service frameworks like apache cxf which may best fit for some special cases, but i would first try to use a framework which is from spring family while using Spring. You should set timeout values on webservicetemplate object to not wait too long if the external system is not working well or you have some problems with the network. Because it directly affects your systems performance. Also here, i suggest you to implement circuit breaker pattern to make your system more robust. You should always isolate your systems performance from other systems that you integrate and in this scenario you can do this by doing the things explained above.
As per my knowledge , you should use Spring boot application with Maven build.
In order to send a REST call to SOAP web service and get back a JSON Response ,you need to follow all of this steps in order :
Business Logic : Mapping the JSON fields such as headers, query-param , body variables to XML Request mandatory fields (either using pojo classes or object-mapper) Reason : Since the SOAP end point will only accept XML Request.
Service Broker Logic : Import "org.springframework.web.client.RestTemplate" and use
**ResponseEntity<String> responseEntity=RestTemplate.exchange(endPointURL, HttpMethod.GET/POST/PUT/DELETE, HttpEntity/headers, uriVariables)**
**endpointURL** -- SOAP End point URL ,that the REST service has to consume.
**HTTPMethod** -- Method Type such as GET ,PUT ,POST ,DELETE etc.
**HTTPEntity** -- Soap requires for mandatory sender/headers/{a}.Make sure that you set your header name and value as key-Valye pair in HTTP headers.
**uriVariables** -- (Object... urivariables) such as String.class ,Integer.class
You should also put the **connectTimeout** ,**isSSLDisabled**,**responseCached** elements while generating request to restTemplate.
responseEntity.getBody() is the XML response after un-marshalling.It can be extracted by using mapper.
XML_BaseResponse response=mapper.readValue(responseEntity.getBody(), XML_BaseResponse.class);
Business Logic : Extract necessary field from XML_BaseResponse and using setter's or getter's functions,set the mandatory fields in the response.
baseResponse.setName(xml_baseResponse.getPersonsName());
baseResponse.setAddress(xml_baseResponse.getAddress());
baseResponse.setCity(xml_baseResponse.getcityName());
Is there any way to achieve multiple responses from a single request using Spring Boot ? If yes, please provide me a link.
HTTP does not work this way. An HTTP request has exactly one response. Spring Boot will not let you send more than one response, because that would be against the HTTP specification and no HTTP clients would be able to figure out what was going on.
There may be another way to accomplish your underlying goals, but whatever it is, it won't involve sending more than one HTTP response to a single HTTP request.
I am coming from servlet/web application world and started learning web services(SOAP based). I have gone through some of the webservice
tutorials. I am trying to draw the parallel between normal http request and webservice request. Here are my observations ;-
1)Both are HTTP request. Webservice is a also post request which contains soap envelope as request body. Soap envelope
is just a normal xml which contains the data
2)java Stub internally marshal the XML , creates HTTP request and send it to consumer
3)Servlet at consumer side intercpets that request and unrmashal it to java object and send it to corresponding service.
Is my observation correct ? I know there may be other complexities but i tried to put the comparison in simple manner.
Your assumptions are generally correct. Yet, the subtelties can lead to huge differences.
Claim 1 : both are HTTP.
SOAP is generally used with an HTTP "binding". Yet it does not have to be that way. SOAP is designed to be fairly transport agnostic. It is not uncommon to have SOAP being used over JMS (although one might consider this an overuse of JMS, and an over architected protocol), it is certainly in production in many places. Rarely seen are SOAP/SMTP or SOAP/TCP without HTTP, but these exist too.
Webservice is a also post request which contains soap envelope as request body
A SOAP call over HTTP is a POST request. It may not be of content-type xml, though, as some variants such as SwA (SOAP with attachments) or XOP+MTOM variants may produce HTTP payloads that are MIME/Multipart (the first part of which is the SOAP Enveloppe in its pure XML form).
This use cas is most common when on is to send large binary content over a SOAP Call, and for which binary encoding may add a large weight to the request (base64 is a 1.3x factor in weight).
java Stub internally marshal the XML, creates HTTP request and send it to consumer
That is the usual way it is done, Axis framework and JAXWS frameworks work primarily this way.
The older SAAJ API, a standard EE API, requires you to build your SOAP Message by hand, using the DOM APIs, (see SOAPMessageFactory), and then send it.
If you look at Spring WS, you'll have something close to your claim, but where each part is fairly exposed and in your control (you may elect to build certain calls with a DOM Api, others by using JAXB marshalling, ...).
3)Servlet at consumer side intercpets that request and unrmashal it to java object and send it to corresponding service
Again, this is how things generaly work. But you can also have an implementation that works outside a servlet container. (See Endpoint Service API in JAX WS).
Your assumptions are right:-
Yes, Servlet request and Web service request both are normal HTTP request and yes, SOAP web service internally use HTTP POST.
Yes,java internally marshal the XML. Also, at client end one java web service client(may be a wrapped in servlet) un-marshal it. A SOAP message or SOAP type web service has many characteristics like:-
SOAP message mostly send data using XML format. XMLs are technology independent. So, SOAP can interact with two heterogeneous web applications built in two separate technologies and exchange data using XML.
SOAP web services send XML using HTTP protocol. Data are sent wrapped in an XML using the payload of HTTP.
SOAP web services can be secured. For an example, all the payment related transactions using credit card and bank info are done using secured SOAP web services.
A SOAP web service accepts XML in request and returns XML in response. In case of errors this return XMLs can also contain SOAP faults. SOAP faults contain the description of error and an error code.
Web services can carry attachment document also like PDF, Word etc. with its XML payload. Java provides separate API for this type of web services. There is an API available in java called SAAJ to accomplish this.
I think that you can find a very good response in this blog post by Ben Klopfer.
Mainly the difference between XML/SOAP vs HTTP/REST is that the former is most response verbose while the latter is lighter.
But this is not the only aspect you have to take into account.
REST represents the state of the resource and is a little bit easier to use and to understand, and always remember that it comes afterwards compared to SOAP.
In addition SOAP it is not limited to using HTTP/HTTPS, but can be also used with other transports like SMTP, JMS, etc.
Resuming the post reminds you:
Use SOAP when:
All you need is simple operations, like read only methods
Implementing a one-way or one-object service for something like data exchange or transfer
You want finer control over the specific transport of data, or can’t always use HTTP
Rigid specifications need to be enforced on incoming requests, and you want to minimize additional documentation needed for use
You can rely on client ability to parse XML, or more preferably SOAP itself
You need built-in error handling when things go wrong with requests
Use REST when:
Operations are complex, like create/read/update/delete on objects
Implementing a multi-faceted service for a variety of different objects
You want to easily and quickly target a variety of consumer end user devices as clients
Requests are generally stateless, like call and response compared to a conversation
Your clients may have limited bandwidth or processing power
You can leave it up to the client to get their requests correct and to deal with problems
If I have some APIs using SOAP, how do I know if the methods requires a GET, POST or other?
Also, What are the consequence (not even sure it would work) if I use a GET for a SOAP web service requiring a POST? or vice-versa?
Thanks, I'm still trying to get a good understanding on how to consume web services. I got some working with simple API's, but really having problem using a web service that returns is used to download files. Thanks again.
HTTP GET requests generally do not have a content part which how the SOAP message is transmitted to the server. This is why POST is used.
Specifically from RFC 2616 Section 4.3. Emphasis mine.
A message-body MUST NOT be included in a request if the specification
of the request method (section 5.1.1) does not allow sending an
entity-body in requests. A server SHOULD read and forward a
message-body on any request; if the request method does not include
defined semantics for an entity-body, then the message-body SHOULD be
ignored when handling the request.
EDIT:
As of SOAP 1.2 it is possible to use HTTP GET method and get a SOAP response back. I recommend reading the SOAP 1.2 primer Section 4.1 for details about which HTTP methods are appropriate in what situations.
I've got a terrible SOAP WSDL, and all attempts to do a codegen with JAXB/CXF/Axis failed to generate usable code. In order to build a web service out of it, I started implementing it out of a Spring MVC Controller.
Things were OK until one of the services had to receive a SOAP/MTOM+XOP request. I tried using Commons FileUpload through org.springframework.web.multipart.commons.CommonsMultipartResolver but it returns no files. That's understandable because the MTOM attachments are not files per se. And they do not have a file name. Just a Content-ID.
Is there a way to obtain these attachments?