CODEWITHSUNDEEP
httpmime
user2922486
user2922486

Reputation: 1

Content-transfer-Encoding Header of MIME with HTTP

I have a doubt regarding sending of mime attachments over HTTP:

in http specs the following is quoted :

“C.4 No Content-Transfer-Encoding: HTTP does not use the Content-Transfer-Encoding (CTE) field of RFC 1521. Proxies and gateways from MIME-compliant protocols to HTTP must remove any non-identity CTE ("quoted-printable" or "base64") encoding prior to delivering the response message to an HTTP client. Proxies and gateways from HTTP to MIME-compliant protocols are responsible for ensuring that the message is in the correct format and encoding for safe transport on that protocol, where "safe transport" is defined by the limitations of the protocol being used. Such a proxy or gateway should label the data with an appropriate Content-Transfer-Encoding if doing so will improve the likelihood of safe transport over the destination protocol.”

Does this mean that specifically for sending MIME attachments only over http, we shouldn't specify content-transfer-encoding as quoted-printable or base64 ?

Also, what is the behavior of conetent-transfer-encoding when i send such attachments over other transports like JMS, or over Mail? For example in a SOAP over JMS message?

Also the found following relevant from RFC 4130 :

“5.2. Unused MIME Headers and Operations 5.2.1. Content-Transfer-Encoding Not Used in HTTP Transport HTTP can handle binary data and so there is no need to use the content transfer encodings of MIME [1]. This difference is discussed in [3], Section 19.4.5. However, a content transfer encoding value of binary or 8-bit is permissible but not required. The absence of this header MUST NOT result in transaction failure. Content transfer encoding of MIME body parts within the AS2 message body is also allowed.”

So i am basically thoroughly confused over the behavior of mime attachments specific to the HTTP protocol, and would like to get its behavior clarified.

Upvotes: 0

Views: 1424

Answers (1)

Julian Reschke
Julian Reschke

Reputation: 41997

HTTP is not MIME, it just borrows from the MIME message format. Payloads in HTTP are binary, and there simply is no Content-Transfer-Encoding header field. You can specify it, but it has zero effect and keeps distracting people looking at wire traces.

Upvotes: 1

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