Do not drop content-type/content-encoding headers from http entity

[chudinovskikh]

Fixed missing 'content-type'/'content-encoding' headers in case of retries.

AWSRequestSigningApacheInterceptor incorrectly replaces HttpEnity during request signature. Basically, it does not copy content-encoding/content-type headers from HttpEnity. As a result if a retry is happening those headers are lost.

Full chain of events:

• http request with attached http entity is built, httpentity#contentEncoding and httpentity#contentType are set;
• RetryExec caches headers from original http request (https://github.com/apache/httpcomponents-client/blob/4.5.x/httpclient/src/main/java/org/apache/http/impl/execchain/RetryExec.java#L86);
• HttpClient request interceptor populates request headers from http entity (https://github.com/apache/httpcomponents-core/blob/4.4.x/httpcore/src/main/java/org/apache/http/protocol/RequestContent.java#L117);
• AWSRequestSigningApacheInterceptor signs the request and replaces existing http entity with a new one (https://github.com/awslabs/aws-request-signing-apache-interceptor/blob/master/src/main/java/com/amazonaws/http/AWSRequestSigningApacheInterceptor.java#L125), contentType/contentEncoding headers are not set for the new http entity;
• Retriable IO Exception is thrown,
• RetryExec resets http headers with original ones (https://github.com/apache/httpcomponents-client/blob/4.5.x/httpclient/src/main/java/org/apache/http/impl/execchain/RetryExec.java#L111);
• HttpClient request interceptor tries to populate headers from http entity, but http entity does not have contentType/contentEncoding headers set, so the request does not have contentType/contentEncoding headers;
• AWSRequestSigningApacheInterceptor signs the request (without contentType/contentEncoding headers);
• The request is sent (without contentType/contentEncoding headers);

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By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[noslowerdna]

@chudinovskikh What is the status of this pull request?

[chudinovskikh]

Hi @noslowerdna,

Unfortunately never got attention from the owner of this repo. I will try to ping them again.