- Multipart Alternative Mime Format
- Html Mime Types Image
- Html Mime Types Crossword Clue
- Html Mime Type Xlsx
- Html Mime Type Text/html
- Html Mime Types Vsdx
A MIME type is a string identifier composed of two parts: a 'type' and a 'subtype'. The 'type' refers to a logical grouping of many MIME types that are closely related to each other; it's no more than a high level category. 'subtypes' are specific to one file type within the 'type'. Definition and Usage. The type attribute specifies the media type of the linked document/resource. The most common value of type is 'text/css'. If you omit the type attribute, the browser will look at the rel attribute to guess the correct type. HTML: MIME Type. This HTML tutorial explains the basics of MIME Type with syntax and examples. A MIME type (or media type) is an identifier for file formats or format contents on the Internet. MIME stands for Multipurpose Internet Mail Extensions and all MIME types are officially maintained by the Internet Assigned Numbers. The presence of a MIME type does not imply the respective files should be published on the Internet. In particular, you will never want to expose files containing private keys (.p8,.p12). Since OpenSSL defaults to PEM encoding, almost all open-source software uses PEM formatted.crt files locally. See Apache modssl, stunnel, etc. A media type (formerly known as MIME type) is a two-part identifier for file formats and format contents transmitted on the Internet.The Internet Assigned Numbers Authority (IANA) is the official authority for the standardization and publication of these classifications. Media types were originally defined in Request for Comments RFC 2045 (MIME) Part One: Format of Internet Message Bodies (Nov.
A body part is NOT to be interpretedas actually being an RFC 822message. To begin with, NO headerfields are actually required inbody parts. A body part that starts with a blank line, therefore,is allowed and is a body part forwhich all default values are to beassumed. In such a case, theabsence of a Content-Type headerfield implies that the encapsulationis plain US-ASCII text. The only header fields that have definedmeaning for body parts are thosethe names of which begin with 'Content-'. All other header fields are generally to be ignored in bodyparts. Although they should generally be retained in mail processing, they may be discarded by gatewaysif necessary. Such other fieldsare permitted to appear in body parts but should not be depended on.'X-' fields may be created for experimental or private purposes,with the recognition that the informationthey contain may be lost at somegateways.
The distinction between an RFC 822message and a body part is subtle,but important. A gateway betweenInternet and X.400 mail, for example,must be able to tell the difference between a body part that containsan image and a body part that containsan encapsulated message, the bodyof which is an image. In orderto represent the latter, the bodypart must have 'Content-Type: message',and its body (after the blankline) must be the encapsulated message,with its own 'Content-Type: image'header field. The use of similar syntax facilitates the conversionof messages to body parts, andvice versa, but the distinction betweenthe two must be understood byimplementors. (For the special casein which all parts actually aremessages, a 'digest' subtype is also defined.)
As stated previously, each bodypart is preceded by an encapsulationboundary. The encapsulation boundaryMUST NOT appear inside any of theencapsulated parts. Thus, it is crucial that the composing agent be able to choose and specifythe unique boundary that will separatethe parts.
All present and future subtypes ofthe 'multipart' type must use an identical syntax. Subtypes may differ in their semantics, andmay impose additional restrictionson syntax, but must conform tothe required syntax for the multipart type. This requirement ensuresthat all conformant user agentswill at least be able to recognizeand separate the parts of any multipart entity, even of an unrecognized subtype.
As stated in the definition of theContent-Transfer-Encoding field,no encoding other than '7bit', '8bit',or 'binary' is permitted for entitiesof type 'multipart'. The multipart delimiters and header fieldsare always 7-bit ASCII in any case,and data within the body parts canbe encoded on a part-by-partbasis, with Content-Transfer-Encodingfields for each appropriate bodypart.
Mail gateways, relays, and othermail handling agents are commonlyknown to alter the top-level headerof an RFC 822 message. In particular,they frequently add, remove, or reorder header fields. Suchalterations are explicitly forbiddenfor the body part headers embeddedin the bodies of messages oftype 'multipart.'
7.2.1 Multipart: The commonsyntax
All subtypes of 'multipart' sharea common syntax, defined in this section. A simple example of amultipart message also appearsin this section. An example of amore complex multipart messageis given in Appendix C.The Content-Type field for multipartentities requires one parameter, 'boundary', which is used to specify the encapsulation boundary. The encapsulation boundary is defined as a line consisting entirely of two hyphen characters('-', decimal code 45) followed by the boundary parameter valuefrom the Content-Type header field.
NOTE: The hyphens are for roughcompatibility with the earlierRFC 934 method of message encapsulation,and for ease of searching for the boundaries in some implementations. However, it shouldbe noted that multipart messages are NOT completely compatible with RFC 934 encapsulations;in particular, they do not obeyRFC 934 quoting conventions forembedded lines that begin with hyphens. This mechanism waschosen over the RFC 934 mechanismbecause the latter causes lines togrow with each level of quoting.The combination of this growth withthe fact that SMTP implementationssometimes wrap long lines madethe RFC 934 mechanism unsuitablefor use in the event that deeply-nestedmultipart structuring is ever desired.
Thus, a typical multipart Content-Typeheader field might look likethis: This indicates that the entity consistsof several parts, each itselfwith a structure that is syntacticallyidentical to an RFC 822 message,except that the header area mightbe completely empty, and thatthe parts are each preceded by the line Note that the encapsulation boundarymust occur at the beginningof a line, i.e., following a CRLF,and that that initial CRLF is consideredto be part of the encapsulation boundary rather than part ofthe preceding part. The boundarymust be followed immediately eitherby another CRLF and the headerfields for the next part, or by twoCRLFs, in which case there areno header fields for the next part(and it is therefore assumed tobe of Content-Type text/plain).
NOTE: The CRLF preceding theencapsulation line is consideredpart of the boundary so that itis possible to have a part thatdoes not end with a CRLF (line break). Body parts that mustbe considered to end with line breaks, therefore, should have two CRLFspreceding the encapsulation line,the first of which is part of thepreceding body part, and the secondof which is part of the encapsulation boundary.
The requirement that the encapsulationboundary begins with a CRLF implies that the body of a multipart entitymust itself begin with a CRLF beforethe first encapsulation line -- that is, if the 'preamble' areais not used, the entity headersmust be followed by TWO CRLFs. Thisis indeed how such entitiesshould be composed. A tolerant mailreading program, however, may interpreta body of type multipart that begins with an encapsulation lineNOT initiated by a CRLF as also being an encapsulation boundary, but a compliant mail sending program must not generate such entities.
Encapsulation boundaries must not appear within the encapsulations,and must be no longer than 70 characters, not counting the two leading hyphens.
The encapsulation boundary followingthe last body part is a distinguisheddelimiter that indicates that nofurther body parts will follow.Such a delimiter is identical to the previous delimiters, withthe addition of two more hyphens at the end of the line: There appears to be room for additionalinformation prior to the firstencapsulation boundary and followingthe final boundary. These areasshould generally be left blank,and implementations should ignoreanything that appears before thefirst boundary or after the lastone.
NOTE: These 'preamble' and 'epilogue'areas are not used because ofthe lack of proper typing of theseparts and the lack of clear semantics for handling these areas at gateways, particularly X.400 gateways.
NOTE: Because encapsulation boundariesmust not appear in the bodyparts being encapsulated, a user agent must exercise care to choosea unique boundary. The boundary in the example above could havebeen the result of an algorithm designed to produce boundaries witha very low probability of already existing in the data to be encapsulatedwithout having to prescan the data. Alternate algorithms might result in more 'readable' boundariesfor a recipient with an old useragent, but would require more attention to the possibility that the boundary might appear in the encapsulated part. The simplest boundary possible is somethinglike '---', with a closing boundaryof '-----'.
As a very simple example, the followingmultipart message has two parts,both of them plain text, oneof them explicitly typed and oneof them implicitly typed: The use of a Content-Type of multipartin a body part within another multipart entity is explicitly allowed. In such cases, for obvious reasons,care must be taken to ensure that each nested multipart entity must use a different boundarydelimiter. See Appendix C for anexample of nested multipart entities.
Multipart Alternative Mime Format
The use of the multipart Content-Typewith only a single body partmay be useful in certain contexts,and is explicitly permitted.
The only mandatory parameter forthe multipart Content-Type isthe boundary parameter, whichconsists of 1 to 70 charactersfrom a set of characters known tobe very robust through emailgateways, and NOT ending with whitespace. (If a boundary appears toend with white space, the white space must be presumed to havebeen added by a gateway, and shouldbe deleted.) It is formallyspecified by the following BNF: Overall, the body of a multipartentity may be specified as follows: NOTE: Conspicuously missing fromthe multipart type is a notionof structured, related body parts.In general, it seems prematureto try to standardize interpartstructure yet. It is recommendedthat those wishing to provide a more structured or integrated multipartmessaging facility should define a subtype of multipart thatis syntactically identical, butthat always expects the inclusionof a distinguished part that canbe used to specify the structure and integration of the other parts,probably referring to them by their Content-ID field. If thisapproach is used, other implementationswill not recognize the new subtype, but will treat it as the primarysubtype (multipart/mixed) and willthus be able to show the user theparts that are recognized.
7.2.2 The Multipart/mixed (primary)subtype
The primary subtype for multipart,'mixed', is intended for use when the body parts are independent andintended to be displayed serially. Any multipart subtypes that an implementation does not recognizeshould be treated as being of subtype'mixed'.7.2.3 The Multipart/alternativesubtype
The multipart/alternative type issyntactically identical to multipart/mixed, but the semantics are different. In particular, each of the partsis an 'alternative' version of the same information. User agentsshould recognize that the contentof the various parts are interchangeable.The user agent should eitherchoose the 'best' type based onthe user's environment and preferences,or offer the user the availablealternatives. In general, choosingthe best type means displayingonly the LAST part that can be displayed. This may be used, for example,to send mail in a fancy text formatin such a way that it can easily be displayed anywhere: In this example, users whose mailsystem understood the 'text/x-whatever'format would see only the fancyversion, while other users wouldsee only the richtext or plain text version, depending on the capabilitiesof their system.In general, user agents that composemultipart/alternative entitiesshould place the body parts in increasingorder of preference, that is, withthe preferred format last. For fancy text, the sending useragent should put the plainest formatfirst and the richest format last. Receiving user agents shouldpick and display the last formatthey are capable of displaying. In the case where one of the alternatives is itself of type 'multipart' and contains unrecognizedsub-parts, the user agent may chooseeither to show that alternative,an earlier alternative, or both.
NOTE: From an implementor's perspective,it might seem more sensible toreverse this ordering, and havethe plainest alternative last.However, placing the plainest alternative first is the friendliest possible option when mutlipart/alternativeentities are viewed using a non-MIME- compliant mail reader. While thisapproach does impose some burdenon compliant mail readers, interoperabilitywith older mail readers was deemedto be more important in this case.
It may be the case that some useragents, if they can recognizemore than one of the formats, willprefer to offer the user the choiceof which format to view. Thismakes sense, for example, if mailincludes both a nicely-formatted image version and an easily-editedtext version. What is mostcritical, however, is that the usernot automatically be shown multipleversions of the same data. Either the user should be shown thelast recognized version or should explicitly be given the choice.
7.2.4 The Multipart/digest subtype
This document defines a 'digest'subtype of the multipart Content-Type. This type is syntactically identical to multipart/mixed, but the semantics are different. In particular, in a digest, the defaultContent-Type value for a body part is changed from 'text/plain' to 'message/rfc822'. This is done to allow a more readable digest format that is largely compatible (except for the quotingconvention) with RFC 934.Html Mime Types Image
A digest in this format might, then,look something like this:
7.2.5 The Multipart/parallelsubtype
This document defines a 'parallel'subtype of the multipart Content-Type. This type is syntactically identical to multipart/mixed, but the semantics are different. In particular, in a parallel entity, all of the parts are intendedto be presented in parallel, i.e., simultaneously, on hardware and software that are capable ofdoing so. Composing agents shouldbe aware that many mail readers will lack this capability and will showthe parts serially in any event.- HTML Tutorial
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MIME (Multipurpose Internet Mail Extension) media types were originally devised so that e-mails could include information other than plain text. MIME media types indicate the following things −
- How different parts of a message, such as text and attachments, are combined into the message.
- The way in which each part of the message is specified.
- The way different items are encoded for transmission so that even software that was designed to work only with ASCII text can process the message.
![Mime Mime](/uploads/1/2/6/5/126511435/170026989.png)
Now MIME types are not just for use with e-mail; they have been adopted by Web servers as a way to tell Web browsers what type of material was being sent to them so that they can cope with that kind of messages correctly.
MIME content types consist of two parts −
- A main type
- A sub-type
The main type is separated from the subtype by a forward slash character. For example, text/html for HTML.
This chapter is organized for the main types −
For example, the text main type contains types of plain text files, such as −
Html Mime Types Crossword Clue
- text/plain for plain text files
- text/html for HTML files
- text/rtf for text files using rich text formatting
![Html Html](/uploads/1/2/6/5/126511435/633999032.png)
Html Mime Type Xlsx
MIME types are officially supposed to be assigned and listed by the Internet Assigned Numbers Authority (IANA).
Html Mime Type Text/html
Many of the popular MIME types in this list (all those begin with 'x-') are not assigned by the IANA and do not have official status. You can see the list of official MIME types at http://www.iana.org/assignments/media-types/. Those preceded with .vnd are vendorspecific.
Html Mime Types Vsdx
When specifying the MIME type of a content-type field you can also indicate the character set for the text being used. If you do not specify a character set, the default is US-ASCII. For example −