ffdev-info · ross-spencer · Jan 4, 2026 · Nov 11, 2025 · Jan 4, 2026 · Jan 4, 2026
diff --git a/.gitignore b/.gitignore
@@ -141,3 +141,4 @@ jsonid-integration-files/
 
 # Secreta
 token.pypi
+jsonid_pronom.xml
diff --git a/README.md b/README.md
@@ -413,6 +413,60 @@ PRONOM IDs that can then be referenced in the JSONID output.
 Evantually, PRONOM or a PRONOM-like tool might host an authoritative version
 of the JSONID registry.
 
+### JSONID for PRONOM Signature Development
+
+JSONID provides a high-level language for output of PRONOM compatible
+signatures. The feature set is still in its BETA phase but JSONID provides
+two distinct capabilities:
+
+#### 1. Registry output
+
+JSONID's registry can be output using the `--pronom` flag. A signature file
+will be created under `jsonid_pronom.xml` which can be imported into DROID
+for identification of document types registered with JSONID.
+
+JSONID's registry is output alongisde a handful of baseline JSON signatures
+designed to capture "plain"-JSON that is not yet encoded in the registry.
+
+#### 2. Signature development
+
+A standalone `json2pronom` utility is provided for creation of potentially
+robust DROID compatible signatures.
+
+As a high-level language, signatures can be defined in easy to understand
+syntax and then output consistently via the `json2pronom` utility. Signatures
+include sensible defaults for whitespace and other aspects that are
+difficult for signature developers to consistently anticipate when writing
+JSON based signatures.
+
+Given a [sample pattern file](./pronom_example/patterns_example.json) a DROID
+compatible snippet can be output as follows (UTF-8 shown for brevity):
+
+<!--markdownlint-disable-->
+
+```xml
+<?xml version="1.0" ?>
+<FFSignatureFile xmlns="http://www.nationalarchives.gov.uk/pronom/SignatureFile" Version="1" DateCreated="2026-01-04T16:14:16Z">
+  <InternalSignatureCollection>
+    <InternalSignature ID="1" Specificity="Specific">
+      <ByteSequence Reference="BOF" Sequence="{0-4095}7B" MinOffset="0" MaxOffset="4095"/>
+      <ByteSequence Reference="VAR" Sequence="226B65793122{0-16}3A" MinOffset="" MaxOffset=""/>
+      <ByteSequence Reference="VAR" Sequence="226B65793222{0-16}3A" MinOffset="" MaxOffset=""/>
+      <ByteSequence Reference="EOF" Sequence="7D{0-4095}" MinOffset="0" MaxOffset="4095"/>
+    </InternalSignature>
+  </InternalSignatureCollection>
+  <FileFormatCollection>
+    <FileFormat ID="1" Name="JSONID2PRONOM Conversion (UTF-8)" PUID="jsonid2pronom/1" Version="" MIMEType="application/json" FormatType="structured text">
+      <InternalSignatureID>1</InternalSignatureID>
+      <Extension>json</Extension>
+    </FileFormat>
+</FFSignatureFile>
+```
+
+<!--markdownlint-enable-->
+
+Feedback on this utility is welcome.
+
 ## Output format
 
 Previously JSONID output YAML containing all result object metadata. It has

diff --git a/docs/jsonid/export.html b/docs/jsonid/export.html
@@ -55,7 +55,7 @@ <h2 class="section-title" id="header-functions">Functions</h2>
 </summary>
 <pre><code class="python">def exportJSON() -&gt; None:  # pylint: disable=C0103
     &#34;&#34;&#34;Export to JSON.&#34;&#34;&#34;
-    logger.debug(&#34;exporting registry ad JSON&#34;)
+    logger.debug(&#34;exporting registry as JSON&#34;)
     data = registry_data.registry()
     json_obj = []
     id_ = {
@@ -74,9 +74,144 @@ <h2 class="section-title" id="header-functions">Functions</h2>
 </details>
 <div class="desc"><p>Export to JSON.</p></div>
 </dd>
+<dt id="src.jsonid.export.export_pronom"><code class="name flex">
+<span>def <span class="ident">export_pronom</span></span>(<span>) ‑> None</span>
+</code></dt>
+<dd>
+<details class="source">
+<summary>
+<span>Expand source code</span>
+</summary>
+<pre><code class="python">def export_pronom() -&gt; None:
+    &#34;&#34;&#34;Export a PRONOM compatible set of signatures.
+
+    Export is done in two phases. A set of proposed &#34;Baseline&#34; JSON
+    signatures to catch many JSON instances.
+
+    Second the JSONID registry is exported.
+
+    Every export has a priority over the other so that there should
+    be no multiple identification results.
+    &#34;&#34;&#34;
+
+    # pylint: disable=R0914; too-many local variables.
+
+    logger.debug(&#34;exporting registry as PRONOM&#34;)
+
+    reg_data = registry_data.registry()
+    formats = []
+
+    encodings = (&#34;UTF-8&#34;, &#34;UTF-16&#34;, &#34;UTF-16BE&#34;, &#34;UTF-32LE&#34;)
+    priorities = []
+
+    increment_id = 0
+
+    for encoding in encodings:
+        all_baseline = pronom.create_baseline_json_sequences(encoding)
+        for baseline in all_baseline:
+            increment_id += 1
+            fmt = pronom.Format(
+                id=increment_id,
+                name=f&#34;JSON (Baseline - fmt/817) ({encoding})&#34;,
+                version=&#34;&#34;,
+                puid=&#34;jsonid:0000&#34;,
+                mime=&#34;application/json&#34;,
+                classification=&#34;structured text&#34;,
+                external_signatures=[
+                    pronom.ExternalSignature(
+                        id=increment_id,
+                        signature=&#34;json&#34;,
+                        type=pronom.EXT,
+                    )
+                ],
+                internal_signatures=[baseline],
+                priorities=priorities,
+            )
+            priorities.append(f&#34;{increment_id}&#34;)
+            formats.append(fmt)
+
+    for encoding in encodings:
+        for entry in reg_data:
+            increment_id += 1
+            json_puid = f&#34;{entry.json()[&#39;identifier&#39;]};{encoding}&#34;
+            name_ = f&#34;{entry.json()[&#39;name&#39;][0][&#39;@en&#39;]} ({encoding})&#34;
+            markers = entry.json()[&#34;markers&#34;]
+            try:
+                mime = entry.json()[&#34;mime&#34;][0]
+            except IndexError:
+                mime = &#34;&#34;
+            try:
+                sequences = pronom.process_markers(
+                    copy.deepcopy(markers),
+                    increment_id,
+                    encoding=encoding,
+                )
+            except pronom.UnprocessableEntity as err:
+                logger.error(
+                    &#34;%s %s: cannot handle: %s&#34;,
+                    json_puid,
+                    name_,
+                    err,
+                )
+                for marker in markers:
+                    logger.debug(&#34;--- START ---&#34;)
+                    logger.debug(&#34;marker: %s&#34;, marker)
+                    logger.debug(&#34;---  END  ---&#34;)
+                continue
+            fmt = pronom.Format(
+                id=increment_id,
+                name=name_,
+                version=&#34;&#34;,
+                puid=json_puid,
+                mime=mime,
+                classification=&#34;structured text&#34;,
+                external_signatures=[
+                    pronom.ExternalSignature(
+                        id=increment_id,
+                        signature=&#34;json&#34;,
+                        type=pronom.EXT,
+                    )
+                ],
+                internal_signatures=sequences,
+                priorities=copy.deepcopy(list(set(priorities))),
+            )
+            priorities.append(f&#34;{increment_id}&#34;)
+            formats.append(fmt)
+
+    pronom.process_formats_and_save(formats, PRONOM_FILENAME)</code></pre>
+</details>
+<div class="desc"><p>Export a PRONOM compatible set of signatures.</p>
+<p>Export is done in two phases. A set of proposed "Baseline" JSON
+signatures to catch many JSON instances.</p>
+<p>Second the JSONID registry is exported.</p>
+<p>Every export has a priority over the other so that there should
+be no multiple identification results.</p></div>
+</dd>
 </dl>
 </section>
 <section>
+<h2 class="section-title" id="header-classes">Classes</h2>
+<dl>
+<dt id="src.jsonid.export.PRONOMException"><code class="flex name class">
+<span>class <span class="ident">PRONOMException</span></span>
+<span>(</span><span>*args, **kwargs)</span>
+</code></dt>
+<dd>
+<details class="source">
+<summary>
+<span>Expand source code</span>
+</summary>
+<pre><code class="python">class PRONOMException(Exception):
+    &#34;&#34;&#34;Exception class if we can&#39;t create a PRONOM signature as expected.&#34;&#34;&#34;</code></pre>
+</details>
+<div class="desc"><p>Exception class if we can't create a PRONOM signature as expected.</p></div>
+<h3>Ancestors</h3>
+<ul class="hlist">
+<li>builtins.Exception</li>
+<li>builtins.BaseException</li>
+</ul>
+</dd>
+</dl>
 </section>
 </article>
 <nav id="sidebar">
@@ -92,6 +227,14 @@ <h2 class="section-title" id="header-functions">Functions</h2>
 <li><h3><a href="#header-functions">Functions</a></h3>
 <ul class="">
 <li><code><a title="src.jsonid.export.exportJSON" href="#src.jsonid.export.exportJSON">exportJSON</a></code></li>
+<li><code><a title="src.jsonid.export.export_pronom" href="#src.jsonid.export.export_pronom">export_pronom</a></code></li>
+</ul>
+</li>
+<li><h3><a href="#header-classes">Classes</a></h3>
+<ul>
+<li>
+<h4><code><a title="src.jsonid.export.PRONOMException" href="#src.jsonid.export.PRONOMException">PRONOMException</a></code></h4>
+</li>
 </ul>
 </li>
 </ul>

diff --git a/docs/jsonid/export_helpers.html b/docs/jsonid/export_helpers.html
@@ -0,0 +1,118 @@
+<!doctype html>
+<html lang="en">
+<head>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width, initial-scale=1, minimum-scale=1">
+<meta name="generator" content="pdoc3 0.11.6">
+<title>src.jsonid.export_helpers API documentation</title>
+<meta name="description" content="Helpers for the export functions.">
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+<script defer src="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/highlight.min.js" integrity="sha512-D9gUyxqja7hBtkWpPWGt9wfbfaMGVt9gnyCvYa+jojwwPHLCzUm5i8rpk7vD7wNee9bA35eYIjobYPaQuKS1MQ==" crossorigin></script>
+<script>window.addEventListener('DOMContentLoaded', () => {
+hljs.configure({languages: ['bash', 'css', 'diff', 'graphql', 'ini', 'javascript', 'json', 'plaintext', 'python', 'python-repl', 'rust', 'shell', 'sql', 'typescript', 'xml', 'yaml']});
+hljs.highlightAll();
+/* Collapse source docstrings */
+setTimeout(() => {
+[...document.querySelectorAll('.hljs.language-python > .hljs-string')]
+.filter(el => el.innerHTML.length > 200 && ['"""', "'''"].includes(el.innerHTML.substring(0, 3)))
+.forEach(el => {
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+d.classList.add('hljs-string');
+d.innerHTML = '<summary>"""</summary>' + el.innerHTML.substring(3);
+el.replaceWith(d);
+});
+}, 100);
+})</script>
+</head>
+<body>
+<main>
+<article id="content">
+<header>
+<h1 class="title">Module <code>src.jsonid.export_helpers</code></h1>
+</header>
+<section id="section-intro">
+<p>Helpers for the export functions.</p>
+</section>
+<section>
+</section>
+<section>
+</section>
+<section>
+<h2 class="section-title" id="header-functions">Functions</h2>
+<dl>
+<dt id="src.jsonid.export_helpers.get_utc_timestamp_now"><code class="name flex">
+<span>def <span class="ident">get_utc_timestamp_now</span></span>(<span>)</span>
+</code></dt>
+<dd>
+<details class="source">
+<summary>
+<span>Expand source code</span>
+</summary>
+<pre><code class="python">def get_utc_timestamp_now():
+    &#34;&#34;&#34;Get a formatted UTC timestamp for &#39;now&#39; that can be used when
+    a timestamp is needed.
+    &#34;&#34;&#34;
+    return datetime.datetime.now(timezone.utc).strftime(UTC_TIME_FORMAT)</code></pre>
+</details>
+<div class="desc"><p>Get a formatted UTC timestamp for 'now' that can be used when
+a timestamp is needed.</p></div>
+</dd>
+<dt id="src.jsonid.export_helpers.new_prettify"><code class="name flex">
+<span>def <span class="ident">new_prettify</span></span>(<span>c)</span>
+</code></dt>
+<dd>
+<details class="source">
+<summary>
+<span>Expand source code</span>
+</summary>
+<pre><code class="python">def new_prettify(c):
+    &#34;&#34;&#34;Remove excess newlines from DOM output.
+
+    via: https://stackoverflow.com/a/14493981
+    &#34;&#34;&#34;
+    reparsed = parseString(c)
+    return &#34;\n&#34;.join(
+        [
+            line
+            for line in reparsed.toprettyxml(indent=&#34; &#34; * 2).split(&#34;\n&#34;)
+            if line.strip()
+        ]
+    )</code></pre>
+</details>
+<div class="desc"><p>Remove excess newlines from DOM output.</p>
+<p>via: <a href="https://stackoverflow.com/a/14493981">https://stackoverflow.com/a/14493981</a></p></div>
+</dd>
+</dl>
+</section>
+<section>
+</section>
+</article>
+<nav id="sidebar">
+<div class="toc">
+<ul></ul>
+</div>
+<ul id="index">
+<li><h3>Super-module</h3>
+<ul>
+<li><code><a title="src.jsonid" href="index.html">src.jsonid</a></code></li>
+</ul>
+</li>
+<li><h3><a href="#header-functions">Functions</a></h3>
+<ul class="">
+<li><code><a title="src.jsonid.export_helpers.get_utc_timestamp_now" href="#src.jsonid.export_helpers.get_utc_timestamp_now">get_utc_timestamp_now</a></code></li>
+<li><code><a title="src.jsonid.export_helpers.new_prettify" href="#src.jsonid.export_helpers.new_prettify">new_prettify</a></code></li>
+</ul>
+</li>
+</ul>
+</nav>
+</main>
+<footer id="footer">
+<p>Generated by <a href="https://pdoc3.github.io/pdoc" title="pdoc: Python API documentation generator"><cite>pdoc</cite> 0.11.6</a>.</p>
+</footer>
+</body>
+</html>
diff --git a/docs/jsonid/helpers.html b/docs/jsonid/helpers.html
@@ -273,19 +273,19 @@ <h2 class="section-title" id="header-functions">Functions</h2>
     # pylint: disable=R0911
 
     if replace_me.__name__ == &#34;dict&#34;:
-        return &#34;map&#34;
+        return TYPE_MAP
     if replace_me.__name__ == &#34;int&#34;:
-        return &#34;integer&#34;
+        return TYPE_INTEGER
     if replace_me.__name__ == &#34;list&#34;:
-        return &#34;list&#34;
+        return TYPE_LIST
     if replace_me.__name__ == &#34;str&#34;:
-        return &#34;string&#34;
+        return TYPE_STRING
     if replace_me.__name__ == &#34;float&#34;:
-        return &#34;float&#34;
+        return TYPE_FLOAT
     if replace_me.__name__ == &#34;bool&#34;:
-        return &#34;bool&#34;
+        return TYPE_BOOL
     if replace_me.__name__ == &#34;NoneType&#34;:
-        return &#34;NoneType&#34;
+        return TYPE_NONE
     if not isinstance(replace_me, type):
         pass
     return replace_me</code></pre>
Original file line number	Diff line number	Diff line change
Expand Up		@@ -141,3 +141,4 @@ jsonid-integration-files/

		# Secreta
		token.pypi
		jsonid_pronom.xml