\href{https://github.com/npm/ssri}{\texttt{ {\ttfamily ssri}}}, short for Standard Subresource Integrity, is a Node.\+js utility for parsing, manipulating, serializing, generating, and verifying \href{https://w3c.github.io/webappsec/specs/subresourceintegrity/}{\texttt{ Subresource Integrity}} hashes.\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28835}{}\doxysection{Install}\label{md_sfcode_node_modules_ssri_README_autotoc_md28835}
{\ttfamily \$ npm install -\/-\/save ssri}\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28836}{}\doxysection{Table of Contents}\label{md_sfcode_node_modules_ssri_README_autotoc_md28836}

\begin{DoxyItemize}
\item \href{\#example}{\texttt{ Example}}
\item \href{\#features}{\texttt{ Features}}
\item \href{\#contributing}{\texttt{ Contributing}}
\item \href{\#api}{\texttt{ API}}
\begin{DoxyItemize}
\item Parsing \& Serializing
\begin{DoxyItemize}
\item \href{\#parse}{\texttt{ {\ttfamily parse}}}
\item \href{\#stringify}{\texttt{ {\ttfamily stringify}}}
\item \href{\#integrity-concat}{\texttt{ {\ttfamily Integrity\#concat}}}
\item \href{\#integrity-merge}{\texttt{ {\ttfamily Integrity\#merge}}}
\item \href{\#integrity-to-string}{\texttt{ {\ttfamily Integrity\#to\+String}}}
\item \href{\#integrity-to-json}{\texttt{ {\ttfamily Integrity\#to\+JSON}}}
\item \href{\#integrity-match}{\texttt{ {\ttfamily Integrity\#match}}}
\item \href{\#integrity-pick-algorithm}{\texttt{ {\ttfamily Integrity\#pick\+Algorithm}}}
\item \href{\#integrity-hex-digest}{\texttt{ {\ttfamily Integrity\#hex\+Digest}}}
\end{DoxyItemize}
\item Integrity Generation
\begin{DoxyItemize}
\item \href{\#from-hex}{\texttt{ {\ttfamily from\+Hex}}}
\item \href{\#from-data}{\texttt{ {\ttfamily from\+Data}}}
\item \href{\#from-stream}{\texttt{ {\ttfamily from\+Stream}}}
\item \href{\#create}{\texttt{ {\ttfamily create}}}
\end{DoxyItemize}
\item Integrity Verification
\begin{DoxyItemize}
\item \href{\#check-data}{\texttt{ {\ttfamily check\+Data}}}
\item \href{\#check-stream}{\texttt{ {\ttfamily check\+Stream}}}
\item \href{\#integrity-stream}{\texttt{ {\ttfamily integrity\+Stream}}}
\end{DoxyItemize}
\end{DoxyItemize}
\end{DoxyItemize}\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28837}{}\doxysubsection{Example}\label{md_sfcode_node_modules_ssri_README_autotoc_md28837}

\begin{DoxyCode}{0}
\DoxyCodeLine{const ssri = require('ssri')}
\DoxyCodeLine{}
\DoxyCodeLine{const integrity = 'sha512-\/9KhgCRIx/AmzC8xqYJTZRrnO8OW2Pxyl2DIMZSBOr0oDvtEFyht3xpp71j/r/pAe1DM+JI/A+line3jUBgzQ7A==?foo'}
\DoxyCodeLine{}
\DoxyCodeLine{// Parsing and serializing}
\DoxyCodeLine{const parsed = ssri.parse(integrity)}
\DoxyCodeLine{ssri.stringify(parsed) // === integrity (works on non-\/Integrity objects)}
\DoxyCodeLine{parsed.toString() // === integrity}
\DoxyCodeLine{}
\DoxyCodeLine{// Async stream functions}
\DoxyCodeLine{ssri.checkStream(fs.createReadStream('./my-\/file'), integrity).then(...)}
\DoxyCodeLine{ssri.fromStream(fs.createReadStream('./my-\/file')).then(sri => \{}
\DoxyCodeLine{  sri.toString() === integrity}
\DoxyCodeLine{\})}
\DoxyCodeLine{fs.createReadStream('./my-\/file').pipe(ssri.createCheckerStream(sri))}
\DoxyCodeLine{}
\DoxyCodeLine{// Sync data functions}
\DoxyCodeLine{ssri.fromData(fs.readFileSync('./my-\/file')) // === parsed}
\DoxyCodeLine{ssri.checkData(fs.readFileSync('./my-\/file'), integrity) // => 'sha512' }

\end{DoxyCode}
\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28838}{}\doxysubsection{Features}\label{md_sfcode_node_modules_ssri_README_autotoc_md28838}

\begin{DoxyItemize}
\item Parses and stringifies SRI strings.
\item Generates SRI strings from raw data or Streams.
\item Strict standard compliance.
\item {\ttfamily ?foo} metadata option support.
\item Multiple entries for the same algorithm.
\item Object-\/based integrity hash manipulation.
\item Small footprint\+: no dependencies, concise implementation.
\item Full test coverage.
\item Customizable algorithm picker.
\end{DoxyItemize}\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28839}{}\doxysubsection{Contributing}\label{md_sfcode_node_modules_ssri_README_autotoc_md28839}
The ssri team enthusiastically welcomes contributions and project participation! There\textquotesingle{}s a bunch of things you can do if you want to contribute! The ContributorGuide"{} has all the information you need for everything from reporting bugs to contributing entire new features. Please don\textquotesingle{}t hesitate to jump in if you\textquotesingle{}d like to, or even ask us questions if something isn\textquotesingle{}t clear.\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28840}{}\doxysubsection{API}\label{md_sfcode_node_modules_ssri_README_autotoc_md28840}
\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28841}{}\doxysubsubsection{$<$a name=\char`\"{}parse\char`\"{}$>$$<$/a$>$ $<$tt$>$$>$ ssri.\+parse(sri, \mbox{[}opts\mbox{]}) -\/$>$ Integrity$<$/tt$>$}\label{md_sfcode_node_modules_ssri_README_autotoc_md28841}
Parses {\ttfamily sri} into an {\ttfamily Integrity} data structure. {\ttfamily sri} can be an integrity string, an {\ttfamily Hash}-\/like with {\ttfamily digest} and {\ttfamily algorithm} fields and an optional {\ttfamily options} field, or an {\ttfamily Integrity}-\/like object. The resulting object will be an {\ttfamily Integrity} instance that has this shape\+:


\begin{DoxyCode}{0}
\DoxyCodeLine{\{}
\DoxyCodeLine{  'sha1': [\{algorithm: 'sha1', digest: 'deadbeef', options: []\}],}
\DoxyCodeLine{  'sha512': [}
\DoxyCodeLine{    \{algorithm: 'sha512', digest: 'c0ffee', options: []\},}
\DoxyCodeLine{    \{algorithm: 'sha512', digest: 'bad1dea', options: ['foo']\}}
\DoxyCodeLine{  ],}
\DoxyCodeLine{\} }

\end{DoxyCode}


If {\ttfamily opts.\+single} is truthy, a single {\ttfamily Hash} object will be returned. That is, a single object that looks like {\ttfamily \{algorithm, digest, options\}}, as opposed to a larger object with multiple of these.

If {\ttfamily opts.\+strict} is truthy, the resulting object will be filtered such that it strictly follows the Subresource Integrity spec, throwing away any entries with any invalid components. This also means a restricted set of algorithms will be used -- the spec limits them to {\ttfamily sha256}, {\ttfamily sha384}, and {\ttfamily sha512}.

Strict mode is recommended if the integrity strings are intended for use in browsers, or in other situations where strict adherence to the spec is needed.\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28842}{}\doxyparagraph{Example}\label{md_sfcode_node_modules_ssri_README_autotoc_md28842}

\begin{DoxyCode}{0}
\DoxyCodeLine{ssri.parse('sha512-\/9KhgCRIx/AmzC8xqYJTZRrnO8OW2Pxyl2DIMZSBOr0oDvtEFyht3xpp71j/r/pAe1DM+JI/A+line3jUBgzQ7A==?foo') // -\/> Integrity object }

\end{DoxyCode}
\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28843}{}\doxysubsubsection{$<$a name=\char`\"{}stringify\char`\"{}$>$$<$/a$>$ $<$tt$>$$>$ ssri.\+stringify(sri, \mbox{[}opts\mbox{]}) -\/$>$ String$<$/tt$>$}\label{md_sfcode_node_modules_ssri_README_autotoc_md28843}
This function is identical to \href{\#integrity-to-string}{\texttt{ {\ttfamily Integrity\#to\+String()}}}, except it can be used on {\itshape any} object that \href{\#parse}{\texttt{ {\ttfamily parse}}} can handle -- that is, a string, an {\ttfamily Hash}-\/like, or an {\ttfamily Integrity}-\/like.

The {\ttfamily opts.\+sep} option defines the string to use when joining multiple entries together. To be spec-\/compliant, this {\itshape must} be whitespace. The default is a single space (`' \textquotesingle{}\`{}).

If {\ttfamily opts.\+strict} is true, the integrity string will be created using strict parsing rules. See \href{\#parse}{\texttt{ {\ttfamily ssri.\+parse}}}.\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28844}{}\doxyparagraph{Example}\label{md_sfcode_node_modules_ssri_README_autotoc_md28844}

\begin{DoxyCode}{0}
\DoxyCodeLine{// Useful for cleaning up input SRI strings:}
\DoxyCodeLine{ssri.stringify('\(\backslash\)n\(\backslash\)rsha512-\/foo\(\backslash\)n\(\backslash\)t\(\backslash\)tsha384-\/bar')}
\DoxyCodeLine{// -\/> 'sha512-\/foo sha384-\/bar'}
\DoxyCodeLine{}
\DoxyCodeLine{// Hash-\/like: only a single entry.}
\DoxyCodeLine{ssri.stringify(\{}
\DoxyCodeLine{  algorithm: 'sha512',}
\DoxyCodeLine{  digest:'9KhgCRIx/AmzC8xqYJTZRrnO8OW2Pxyl2DIMZSBOr0oDvtEFyht3xpp71j/r/pAe1DM+JI/A+line3jUBgzQ7A==',}
\DoxyCodeLine{  options: ['foo']}
\DoxyCodeLine{\})}
\DoxyCodeLine{// -\/>}
\DoxyCodeLine{// 'sha512-\/9KhgCRIx/AmzC8xqYJTZRrnO8OW2Pxyl2DIMZSBOr0oDvtEFyht3xpp71j/r/pAe1DM+JI/A+line3jUBgzQ7A==?foo'}
\DoxyCodeLine{}
\DoxyCodeLine{// Integrity-\/like: full multi-\/entry syntax. Similar to output of `ssri.parse`}
\DoxyCodeLine{ssri.stringify(\{}
\DoxyCodeLine{  'sha512': [}
\DoxyCodeLine{    \{}
\DoxyCodeLine{      algorithm: 'sha512',}
\DoxyCodeLine{      digest:'9KhgCRIx/AmzC8xqYJTZRrnO8OW2Pxyl2DIMZSBOr0oDvtEFyht3xpp71j/r/pAe1DM+JI/A+line3jUBgzQ7A==',}
\DoxyCodeLine{      options: ['foo']}
\DoxyCodeLine{    \}}
\DoxyCodeLine{  ]}
\DoxyCodeLine{\})}
\DoxyCodeLine{// -\/>}
\DoxyCodeLine{// 'sha512-\/9KhgCRIx/AmzC8xqYJTZRrnO8OW2Pxyl2DIMZSBOr0oDvtEFyht3xpp71j/r/pAe1DM+JI/A+line3jUBgzQ7A==?foo' }

\end{DoxyCode}
\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28845}{}\doxysubsubsection{$<$a name=\char`\"{}integrity-\/concat\char`\"{}$>$$<$/a$>$ $<$tt$>$$>$ Integrity\#concat(other\+Integrity, \mbox{[}opts\mbox{]}) -\/$>$ Integrity$<$/tt$>$}\label{md_sfcode_node_modules_ssri_README_autotoc_md28845}
Concatenates an {\ttfamily Integrity} object with another Integrity\+Like, or an integrity string.

This is functionally equivalent to concatenating the string format of both integrity arguments, and calling \href{\#ssri-parse}{\texttt{ {\ttfamily ssri.\+parse}}} on the new string.

If {\ttfamily opts.\+strict} is true, the new {\ttfamily Integrity} will be created using strict parsing rules. See \href{\#parse}{\texttt{ {\ttfamily ssri.\+parse}}}.\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28846}{}\doxyparagraph{Example}\label{md_sfcode_node_modules_ssri_README_autotoc_md28846}

\begin{DoxyCode}{0}
\DoxyCodeLine{// This will combine the integrity checks for two different versions of}
\DoxyCodeLine{// your index.js file so you can use a single integrity string and serve}
\DoxyCodeLine{// either of these to clients, from a single `<script>` tag.}
\DoxyCodeLine{const desktopIntegrity = ssri.fromData(fs.readFileSync('./index.desktop.js'))}
\DoxyCodeLine{const mobileIntegrity = ssri.fromData(fs.readFileSync('./index.mobile.js'))}
\DoxyCodeLine{}
\DoxyCodeLine{// Note that browsers (and ssri) will succeed as long as ONE of the entries}
\DoxyCodeLine{// for the *prioritized* algorithm succeeds. That is, in order for this fallback}
\DoxyCodeLine{// to work, both desktop and mobile *must* use the same `algorithm` values.}
\DoxyCodeLine{desktopIntegrity.concat(mobileIntegrity) }

\end{DoxyCode}
\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28847}{}\doxysubsubsection{$<$a name=\char`\"{}integrity-\/merge\char`\"{}$>$$<$/a$>$ $<$tt$>$$>$ Integrity\#merge(other\+Integrity, \mbox{[}opts\mbox{]})$<$/tt$>$}\label{md_sfcode_node_modules_ssri_README_autotoc_md28847}
Safely merges another Integrity\+Like or integrity string into an {\ttfamily Integrity} object.

If the other integrity value has any algorithms in common with the current object, then the hash digests must match, or an error is thrown.

Any new hashes will be added to the current object\textquotesingle{}s set.

This is useful when an integrity value may be upgraded with a stronger algorithm, you wish to prevent accidentally supressing integrity errors by overwriting the expected integrity value.\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28848}{}\doxyparagraph{Example}\label{md_sfcode_node_modules_ssri_README_autotoc_md28848}

\begin{DoxyCode}{0}
\DoxyCodeLine{const data = fs.readFileSync('data.txt')}
\DoxyCodeLine{}
\DoxyCodeLine{// integrity.txt contains 'sha1-\/X1UT+IIv2+UUWvM7ZNjZcNz5XG4='}
\DoxyCodeLine{// because we were young, and didn't realize sha1 would not last}
\DoxyCodeLine{const expectedIntegrity = ssri.parse(fs.readFileSync('integrity.txt', 'utf8'))}
\DoxyCodeLine{const match = ssri.checkData(data, expectedIntegrity, \{}
\DoxyCodeLine{  algorithms: ['sha512', 'sha1']}
\DoxyCodeLine{\})}
\DoxyCodeLine{if (!match) \{}
\DoxyCodeLine{  throw new Error('data corrupted or something!')}
\DoxyCodeLine{\}}
\DoxyCodeLine{}
\DoxyCodeLine{// get a stronger algo!}
\DoxyCodeLine{if (match \&\& match.algorithm !== 'sha512') \{}
\DoxyCodeLine{  const updatedIntegrity = ssri.fromData(data, \{ algorithms: ['sha512'] \})}
\DoxyCodeLine{  expectedIntegrity.merge(updatedIntegrity)}
\DoxyCodeLine{  fs.writeFileSync('integrity.txt', expectedIntegrity.toString())}
\DoxyCodeLine{  // file now contains}
\DoxyCodeLine{  // 'sha1-\/X1UT+IIv2+UUWvM7ZNjZcNz5XG4= sha512-\/yzd8ELD1piyANiWnmdnpCL5F52f10UfUdEkHywVZeqTt0ymgrxR63Qz0GB7TKPoeeZQmWCaz7T1+9vBnypkYWg=='}
\DoxyCodeLine{\} }

\end{DoxyCode}
\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28849}{}\doxysubsubsection{$<$a name=\char`\"{}integrity-\/to-\/string\char`\"{}$>$$<$/a$>$ $<$tt$>$$>$ Integrity\#to\+String(\mbox{[}opts\mbox{]}) -\/$>$ String$<$/tt$>$}\label{md_sfcode_node_modules_ssri_README_autotoc_md28849}
Returns the string representation of an {\ttfamily Integrity} object. All hash entries will be concatenated in the string by {\ttfamily opts.\+sep}, which defaults to `' \textquotesingle{}\`{}.

If you want to serialize an object that didn\textquotesingle{}t come from an {\ttfamily ssri} function, use \href{\#stringify}{\texttt{ {\ttfamily ssri.\+stringify()}}}.

If {\ttfamily opts.\+strict} is true, the integrity string will be created using strict parsing rules. See \href{\#parse}{\texttt{ {\ttfamily ssri.\+parse}}}.\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28850}{}\doxyparagraph{Example}\label{md_sfcode_node_modules_ssri_README_autotoc_md28850}

\begin{DoxyCode}{0}
\DoxyCodeLine{const integrity = 'sha512-\/9KhgCRIx/AmzC8xqYJTZRrnO8OW2Pxyl2DIMZSBOr0oDvtEFyht3xpp71j/r/pAe1DM+JI/A+line3jUBgzQ7A==?foo'}
\DoxyCodeLine{}
\DoxyCodeLine{ssri.parse(integrity).toString() === integrity }

\end{DoxyCode}
\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28851}{}\doxysubsubsection{$<$a name=\char`\"{}integrity-\/to-\/json\char`\"{}$>$$<$/a$>$ $<$tt$>$$>$ Integrity\#to\+JSON() -\/$>$ String$<$/tt$>$}\label{md_sfcode_node_modules_ssri_README_autotoc_md28851}
Returns the string representation of an {\ttfamily Integrity} object. All hash entries will be concatenated in the string by `' \textquotesingle{}\`{}.

This is a convenience method so you can pass an {\ttfamily Integrity} object directly to {\ttfamily JSON.\+stringify}. For more info check out \href{https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify\#toJSON\%28\%29_behavior}{\texttt{ to\+JSON() behavior on mdn}}.\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28852}{}\doxyparagraph{Example}\label{md_sfcode_node_modules_ssri_README_autotoc_md28852}

\begin{DoxyCode}{0}
\DoxyCodeLine{const integrity = '"{}sha512-\/9KhgCRIx/AmzC8xqYJTZRrnO8OW2Pxyl2DIMZSBOr0oDvtEFyht3xpp71j/r/pAe1DM+JI/A+line3jUBgzQ7A==?foo"{}'}
\DoxyCodeLine{}
\DoxyCodeLine{JSON.stringify(ssri.parse(integrity)) === integrity }

\end{DoxyCode}
\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28853}{}\doxysubsubsection{$<$a name=\char`\"{}integrity-\/match\char`\"{}$>$$<$/a$>$ $<$tt$>$$>$ Integrity\#match(sri, \mbox{[}opts\mbox{]}) -\/$>$ Hash $\vert$ false$<$/tt$>$}\label{md_sfcode_node_modules_ssri_README_autotoc_md28853}
Returns the matching (truthy) hash if {\ttfamily Integrity} matches the argument passed as {\ttfamily sri}, which can be anything that \href{\#parse}{\texttt{ {\ttfamily parse}}} will accept. {\ttfamily opts} will be passed through to {\ttfamily parse} and \href{\#integrity-pick-algorithm}{\texttt{ {\ttfamily pick\+Algorithm()}}}.\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28854}{}\doxyparagraph{Example}\label{md_sfcode_node_modules_ssri_README_autotoc_md28854}

\begin{DoxyCode}{0}
\DoxyCodeLine{const integrity = 'sha512-\/9KhgCRIx/AmzC8xqYJTZRrnO8OW2Pxyl2DIMZSBOr0oDvtEFyht3xpp71j/r/pAe1DM+JI/A+line3jUBgzQ7A=='}
\DoxyCodeLine{}
\DoxyCodeLine{ssri.parse(integrity).match(integrity)}
\DoxyCodeLine{// Hash \{}
\DoxyCodeLine{//   digest: '9KhgCRIx/AmzC8xqYJTZRrnO8OW2Pxyl2DIMZSBOr0oDvtEFyht3xpp71j/r/pAe1DM+JI/A+line3jUBgzQ7A=='}
\DoxyCodeLine{//   algorithm: 'sha512'}
\DoxyCodeLine{// \}}
\DoxyCodeLine{}
\DoxyCodeLine{ssri.parse(integrity).match('sha1-\/deadbeef')}
\DoxyCodeLine{// false }

\end{DoxyCode}
\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28855}{}\doxysubsubsection{$<$a name=\char`\"{}integrity-\/pick-\/algorithm\char`\"{}$>$$<$/a$>$ $<$tt$>$$>$ Integrity\#pick\+Algorithm(\mbox{[}opts\mbox{]}) -\/$>$ String$<$/tt$>$}\label{md_sfcode_node_modules_ssri_README_autotoc_md28855}
Returns the \char`\"{}best\char`\"{} algorithm from those available in the integrity object.

If {\ttfamily opts.\+pick\+Algorithm} is provided, it will be passed two algorithms as arguments. ssri will prioritize whichever of the two algorithms is returned by this function. Note that the function may be called multiple times, and it {\bfseries{must}} return one of the two algorithms provided. By default, ssri will make a best-\/effort to pick the strongest/most reliable of the given algorithms. It may intentionally deprioritize algorithms with known vulnerabilities.\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28856}{}\doxyparagraph{Example}\label{md_sfcode_node_modules_ssri_README_autotoc_md28856}

\begin{DoxyCode}{0}
\DoxyCodeLine{ssri.parse('sha1-\/WEakDigEST sha512-\/yzd8ELD1piyANiWnmdnpCL5F52f10UfUdEkHywVZeqTt0ymgrxR63Qz0GB7TKPoeeZQmWCaz7T1').pickAlgorithm() // sha512 }

\end{DoxyCode}
\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28857}{}\doxysubsubsection{$<$a name=\char`\"{}integrity-\/hex-\/digest\char`\"{}$>$$<$/a$>$ $<$tt$>$$>$ Integrity\#hex\+Digest() -\/$>$ String$<$/tt$>$}\label{md_sfcode_node_modules_ssri_README_autotoc_md28857}
{\ttfamily Integrity} is assumed to be either a single-\/hash {\ttfamily Integrity} instance, or a {\ttfamily Hash} instance. Returns its {\ttfamily digest}, converted to a hex representation of the base64 data.\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28858}{}\doxyparagraph{Example}\label{md_sfcode_node_modules_ssri_README_autotoc_md28858}

\begin{DoxyCode}{0}
\DoxyCodeLine{ssri.parse('sha1-\/deadbeef').hexDigest() // '75e69d6de79f' }

\end{DoxyCode}
\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28859}{}\doxysubsubsection{$<$a name=\char`\"{}from-\/hex\char`\"{}$>$$<$/a$>$ $<$tt$>$$>$ ssri.\+from\+Hex(hex\+Digest, algorithm, \mbox{[}opts\mbox{]}) -\/$>$ Integrity$<$/tt$>$}\label{md_sfcode_node_modules_ssri_README_autotoc_md28859}
Creates an {\ttfamily Integrity} object with a single entry, based on a hex-\/formatted hash. This is a utility function to help convert existing shasums to the Integrity format, and is roughly equivalent to something like\+:


\begin{DoxyCode}{0}
\DoxyCodeLine{algorithm + '-\/' + Buffer.from(hexDigest, 'hex').toString('base64') }

\end{DoxyCode}


{\ttfamily opts.\+options} may optionally be passed in\+: it must be an array of option strings that will be added to all generated integrity hashes generated by {\ttfamily from\+Data}. This is a loosely-\/specified feature of SRIs, and currently has no specified semantics besides being {\ttfamily ?}-\/separated. Use at your own risk, and probably avoid if your integrity strings are meant to be used with browsers.

If {\ttfamily opts.\+strict} is true, the integrity object will be created using strict parsing rules. See \href{\#parse}{\texttt{ {\ttfamily ssri.\+parse}}}.

If {\ttfamily opts.\+single} is true, a single {\ttfamily Hash} object will be returned.\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28860}{}\doxyparagraph{Example}\label{md_sfcode_node_modules_ssri_README_autotoc_md28860}

\begin{DoxyCode}{0}
\DoxyCodeLine{ssri.fromHex('75e69d6de79f', 'sha1').toString() // 'sha1-\/deadbeef' }

\end{DoxyCode}
\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28861}{}\doxysubsubsection{$<$a name=\char`\"{}from-\/data\char`\"{}$>$$<$/a$>$ $<$tt$>$$>$ ssri.\+from\+Data(data, \mbox{[}opts\mbox{]}) -\/$>$ Integrity$<$/tt$>$}\label{md_sfcode_node_modules_ssri_README_autotoc_md28861}
Creates an {\ttfamily Integrity} object from either string or {\ttfamily Buffer} data, calculating all the requested hashes and adding any specified options to the object.

{\ttfamily opts.\+algorithms} determines which algorithms to generate hashes for. All results will be included in a single {\ttfamily Integrity} object. The default value for {\ttfamily opts.\+algorithms} is `\mbox{[}\textquotesingle{}sha512'\mbox{]}{\ttfamily . All algorithm strings must be hashes listed in}crypto.\+get\+Hashes()\`{} for the host Node.\+js platform.

{\ttfamily opts.\+options} may optionally be passed in\+: it must be an array of option strings that will be added to all generated integrity hashes generated by {\ttfamily from\+Data}. This is a loosely-\/specified feature of SRIs, and currently has no specified semantics besides being {\ttfamily ?}-\/separated. Use at your own risk, and probably avoid if your integrity strings are meant to be used with browsers.

If {\ttfamily opts.\+strict} is true, the integrity object will be created using strict parsing rules. See \href{\#parse}{\texttt{ {\ttfamily ssri.\+parse}}}.\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28862}{}\doxyparagraph{Example}\label{md_sfcode_node_modules_ssri_README_autotoc_md28862}

\begin{DoxyCode}{0}
\DoxyCodeLine{const integrityObj = ssri.fromData('foobarbaz', \{}
\DoxyCodeLine{  algorithms: ['sha256', 'sha384', 'sha512']}
\DoxyCodeLine{\})}
\DoxyCodeLine{integrity.toString('\(\backslash\)n')}
\DoxyCodeLine{// -\/>}
\DoxyCodeLine{// sha256-\/l981iLWj8kurw4UbNy8Lpxqdzd7UOxS50Glhv8FwfZ0=}
\DoxyCodeLine{// sha384-\/irnCxQ0CfQhYGlVAUdwTPC9bF3+YWLxlaDGM4xbYminxpbXEq+D+2GCEBTxcjES9}
\DoxyCodeLine{// sha512-\/yzd8ELD1piyANiWnmdnpCL5F52f10UfUdEkHywVZeqTt0ymgrxR63Qz0GB7TKPoeeZQmWCaz7T1+9vBnypkYWg== }

\end{DoxyCode}
\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28863}{}\doxysubsubsection{$<$a name=\char`\"{}from-\/stream\char`\"{}$>$$<$/a$>$ $<$tt$>$$>$ ssri.\+from\+Stream(stream, \mbox{[}opts\mbox{]}) -\/$>$ Promise$<$\+Integrity$>$$<$/tt$>$}\label{md_sfcode_node_modules_ssri_README_autotoc_md28863}
Returns a Promise of an Integrity object calculated by reading data from a given {\ttfamily stream}.

It accepts both {\ttfamily opts.\+algorithms} and {\ttfamily opts.\+options}, which are documented as part of \href{\#from-data}{\texttt{ {\ttfamily ssri.\+from\+Data}}}.

Additionally, {\ttfamily opts.\+Promise} may be passed in to inject a Promise library of choice. By default, ssri will use Node\textquotesingle{}s built-\/in Promises.

If {\ttfamily opts.\+strict} is true, the integrity object will be created using strict parsing rules. See \href{\#parse}{\texttt{ {\ttfamily ssri.\+parse}}}.\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28864}{}\doxyparagraph{Example}\label{md_sfcode_node_modules_ssri_README_autotoc_md28864}

\begin{DoxyCode}{0}
\DoxyCodeLine{ssri.fromStream(fs.createReadStream('index.js'), \{}
\DoxyCodeLine{  algorithms: ['sha1', 'sha512']}
\DoxyCodeLine{\}).then(integrity => \{}
\DoxyCodeLine{  return ssri.checkStream(fs.createReadStream('index.js'), integrity)}
\DoxyCodeLine{\}) // succeeds }

\end{DoxyCode}
\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28865}{}\doxysubsubsection{$<$a name=\char`\"{}create\char`\"{}$>$$<$/a$>$ $<$tt$>$$>$ ssri.\+create(\mbox{[}opts\mbox{]}) -\/$>$ $<$\+Hash$>$$<$/tt$>$}\label{md_sfcode_node_modules_ssri_README_autotoc_md28865}
Returns a Hash object with {\ttfamily update($<$Buffer or string$>$\mbox{[},enc\mbox{]})} and {\ttfamily digest()} methods.

The Hash object provides the same methods as \href{https://nodejs.org/dist/latest-v6.x/docs/api/crypto.html\#crypto_class_hash}{\texttt{ crypto class Hash}}. {\ttfamily digest()} accepts no arguments and returns an Integrity object calculated by reading data from calls to update.

It accepts both {\ttfamily opts.\+algorithms} and {\ttfamily opts.\+options}, which are documented as part of \href{\#from-data}{\texttt{ {\ttfamily ssri.\+from\+Data}}}.

If {\ttfamily opts.\+strict} is true, the integrity object will be created using strict parsing rules. See \href{\#parse}{\texttt{ {\ttfamily ssri.\+parse}}}.\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28866}{}\doxyparagraph{Example}\label{md_sfcode_node_modules_ssri_README_autotoc_md28866}

\begin{DoxyCode}{0}
\DoxyCodeLine{const integrity = ssri.create().update('foobarbaz').digest()}
\DoxyCodeLine{integrity.toString()}
\DoxyCodeLine{// -\/>}
\DoxyCodeLine{// sha512-\/yzd8ELD1piyANiWnmdnpCL5F52f10UfUdEkHywVZeqTt0ymgrxR63Qz0GB7TKPoeeZQmWCaz7T1+9vBnypkYWg== }

\end{DoxyCode}
\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28867}{}\doxysubsubsection{$<$a name=\char`\"{}check-\/data\char`\"{}$>$$<$/a$>$ $<$tt$>$$>$ ssri.\+check\+Data(data, sri, \mbox{[}opts\mbox{]}) -\/$>$ Hash$\vert$false$<$/tt$>$}\label{md_sfcode_node_modules_ssri_README_autotoc_md28867}
Verifies {\ttfamily data} integrity against an {\ttfamily sri} argument. {\ttfamily data} may be either a {\ttfamily String} or a {\ttfamily Buffer}, and {\ttfamily sri} can be any subresource integrity representation that \href{\#parse}{\texttt{ {\ttfamily ssri.\+parse}}} can handle.

If verification succeeds, {\ttfamily check\+Data} will return the name of the algorithm that was used for verification (a truthy value). Otherwise, it will return {\ttfamily false}.

If {\ttfamily opts.\+pick\+Algorithm} is provided, it will be used by \href{\#integrity-pick-algorithm}{\texttt{ {\ttfamily Integrity\#pick\+Algorithm}}} when deciding which of the available digests to match against.

If {\ttfamily opts.\+error} is true, and verification fails, {\ttfamily check\+Data} will throw either an {\ttfamily EBADSIZE} or an {\ttfamily EINTEGRITY} error, instead of just returning false.\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28868}{}\doxyparagraph{Example}\label{md_sfcode_node_modules_ssri_README_autotoc_md28868}

\begin{DoxyCode}{0}
\DoxyCodeLine{const data = fs.readFileSync('index.js')}
\DoxyCodeLine{ssri.checkData(data, ssri.fromData(data)) // -\/> 'sha512'}
\DoxyCodeLine{ssri.checkData(data, 'sha256-\/l981iLWj8kurw4UbNy8Lpxqdzd7UOxS50Glhv8FwfZ0')}
\DoxyCodeLine{ssri.checkData(data, 'sha1-\/BaDDigEST') // -\/> false}
\DoxyCodeLine{ssri.checkData(data, 'sha1-\/BaDDigEST', \{error: true\}) // -\/> Error! EINTEGRITY }

\end{DoxyCode}
\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28869}{}\doxysubsubsection{$<$a name=\char`\"{}check-\/stream\char`\"{}$>$$<$/a$>$ $<$tt$>$$>$ ssri.\+check\+Stream(stream, sri, \mbox{[}opts\mbox{]}) -\/$>$ Promise$<$\+Hash$>$$<$/tt$>$}\label{md_sfcode_node_modules_ssri_README_autotoc_md28869}
Verifies the contents of {\ttfamily stream} against an {\ttfamily sri} argument. {\ttfamily stream} will be consumed in its entirety by this process. {\ttfamily sri} can be any subresource integrity representation that \href{\#parse}{\texttt{ {\ttfamily ssri.\+parse}}} can handle.

{\ttfamily check\+Stream} will return a Promise that either resolves to the {\ttfamily Hash} that succeeded verification, or, if the verification fails or an error happens with {\ttfamily stream}, the Promise will be rejected.

If the Promise is rejected because verification failed, the returned error will have {\ttfamily err.\+code} as {\ttfamily EINTEGRITY}.

If {\ttfamily opts.\+size} is given, it will be matched against the stream size. An error with {\ttfamily err.\+code} {\ttfamily EBADSIZE} will be returned by a rejection if the expected size and actual size fail to match.

If {\ttfamily opts.\+pick\+Algorithm} is provided, it will be used by \href{\#integrity-pick-algorithm}{\texttt{ {\ttfamily Integrity\#pick\+Algorithm}}} when deciding which of the available digests to match against.\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28870}{}\doxyparagraph{Example}\label{md_sfcode_node_modules_ssri_README_autotoc_md28870}

\begin{DoxyCode}{0}
\DoxyCodeLine{const integrity = ssri.fromData(fs.readFileSync('index.js'))}
\DoxyCodeLine{}
\DoxyCodeLine{ssri.checkStream(}
\DoxyCodeLine{  fs.createReadStream('index.js'),}
\DoxyCodeLine{  integrity}
\DoxyCodeLine{)}
\DoxyCodeLine{// -\/>}
\DoxyCodeLine{// Promise<\{}
\DoxyCodeLine{//   algorithm: 'sha512',}
\DoxyCodeLine{//   digest: 'sha512-\/yzd8ELD1piyANiWnmdnpCL5F52f10UfUdEkHywVZeqTt0ymgrxR63Qz0GB7TKPoeeZQmWCaz7T1'}
\DoxyCodeLine{// \}>}
\DoxyCodeLine{}
\DoxyCodeLine{ssri.checkStream(}
\DoxyCodeLine{  fs.createReadStream('index.js'),}
\DoxyCodeLine{  'sha256-\/l981iLWj8kurw4UbNy8Lpxqdzd7UOxS50Glhv8FwfZ0'}
\DoxyCodeLine{) // -\/> Promise<Hash>}
\DoxyCodeLine{}
\DoxyCodeLine{ssri.checkStream(}
\DoxyCodeLine{  fs.createReadStream('index.js'),}
\DoxyCodeLine{  'sha1-\/BaDDigEST'}
\DoxyCodeLine{) // -\/> Promise<Error<\{code: 'EINTEGRITY'\}>> }

\end{DoxyCode}
\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28871}{}\doxysubsubsection{$<$a name=\char`\"{}integrity-\/stream\char`\"{}$>$$<$/a$>$ $<$tt$>$$>$ integrity\+Stream(\mbox{[}opts\mbox{]}) -\/$>$ Integrity\+Stream$<$/tt$>$}\label{md_sfcode_node_modules_ssri_README_autotoc_md28871}
Returns a {\ttfamily Transform} stream that data can be piped through in order to generate and optionally check data integrity for piped data. When the stream completes successfully, it emits {\ttfamily size} and {\ttfamily integrity} events, containing the total number of bytes processed and a calculated {\ttfamily Integrity} instance based on stream data, respectively.

If {\ttfamily opts.\+algorithms} is passed in, the listed algorithms will be calculated when generating the final {\ttfamily Integrity} instance. The default is `\mbox{[}\textquotesingle{}sha512'\mbox{]}\`{}.

If {\ttfamily opts.\+single} is passed in, a single {\ttfamily Hash} instance will be returned.

If {\ttfamily opts.\+integrity} is passed in, it should be an {\ttfamily integrity} value understood by \href{\#parse}{\texttt{ {\ttfamily parse}}} that the stream will check the data against. If verification succeeds, the integrity stream will emit a {\ttfamily verified} event whose value is a single {\ttfamily Hash} object that is the one that succeeded verification. If verification fails, the stream will error with an {\ttfamily EINTEGRITY} error code.

If {\ttfamily opts.\+size} is given, it will be matched against the stream size. An error with {\ttfamily err.\+code} {\ttfamily EBADSIZE} will be emitted by the stream if the expected size and actual size fail to match.

If {\ttfamily opts.\+pick\+Algorithm} is provided, it will be passed two algorithms as arguments. ssri will prioritize whichever of the two algorithms is returned by this function. Note that the function may be called multiple times, and it {\bfseries{must}} return one of the two algorithms provided. By default, ssri will make a best-\/effort to pick the strongest/most reliable of the given algorithms. It may intentionally deprioritize algorithms with known vulnerabilities.\hypertarget{md_sfcode_node_modules_ssri_README_autotoc_md28872}{}\doxyparagraph{Example}\label{md_sfcode_node_modules_ssri_README_autotoc_md28872}

\begin{DoxyCode}{0}
\DoxyCodeLine{const integrity = ssri.fromData(fs.readFileSync('index.js'))}
\DoxyCodeLine{fs.createReadStream('index.js')}
\DoxyCodeLine{.pipe(ssri.integrityStream(\{integrity\})) }

\end{DoxyCode}
 