PxTools · JohannesFinsveen · Jun 5, 2026 · Jun 5, 2026
@@ -0,0 +1,148 @@
+# Links from a dataset
+A table may have links to external resources, e.g. definitions in a classification database or some Statistics home page. PxWebApi needs to provide links to these resources.
+
+The usecase is to provide content in the Information pane of the PxWeb gui:
+
+  ![Information pane in PxWeb](MetaIdInGUI_1.png?raw=true)
+
+
+
+Information for a link includes:
+```
+href:  an url e.g. "https://www.ssb.no/en/aku" , pointing to a resource
+label: text describing the resource, like "Statistics homepage". 
+relation: some description of how the resource is related to the table , like "statistics-homepage". 
+
+type: the mime type of the resource, typically "text/html", but could also be e.g. markdown. 
+```
+
+
+The datasource of the api has a propperty called META-ID. You can attach a META-ID to a table, variable or value.
+The META-ID-values are urns e.g. "STATISTICS:aku". The api transforms it to href,type,label and relation according to rules
+given in a config file.
+
+## META-ID
+The purpose of the META-ID is to identify an external resource, typically an external metadata system. 
+In a Px-file , it may look like:
+```
+META-ID(“my_variable”)=”classifications:region”;
+```
+(For more information about the META-ID keyword, see the PX-file format documentation.)
+
+The META-ID identifies which metadata system the definition resides in and also holds the arguments to navigate to the specific definition within that metadata system.
+The META-ID can also hold information about more than one metadata system if definitions exist in multiple metadata system.
+```
+META-ID(“my_variable”)=”METASYS1:arg1:arg2,METASYS2:arg1:arg2”;
+```
+
+When pxwebapi finds META-ID fields it uses information from a config files to create links.
+## Metaid.config
+If links to metdata systems shall be created, the metaid.config file must be placed in the root directory of the application. 
+In metadid.config you define the URL signatures to your metadata system(s). 
+The URL signatures are divided into three sections in the metaid.config file for attachments at tables, variables and values. The sections are be named:
+* onTable
+* onVariable
+* onValue
+
+The sections are structured in the same way, each contain a list of Metadata systems.
+Each Metadata system has an ID and list of URL signatures grouped by what they contain or how they relate to the table and their content-type. 
+Each URL signature contains information about:
+* Language
+* Label (text) format
+* URL format
+
+The URL format shall contain placeholders {0}, {1} … {n} where the arguments in the META-ID will be inserted. 
+The label format may contain placeholders depending on the attachment level, for values {0} will be replaces by the name of the variable and {1}   by the name of the value.
+For variables its just {0} for the name of the variable. For label formats in the onTable section there are no placeholdes.
+
+For example this fragment of the config file:
+```
+<?xml version="1.0"?>
+<metaId>
+  <onTable>
+    <metaSystem id="STATISTICS">
+      <relationalGroup relation="statistics-homepage" type="text/html">
+        <link pxLang="no" labelStringFormat="Statistikkens hjemmeside" urlStringFormat="https://www.ssb.no/{0}" />
+        <link pxLang="en" labelStringFormat="Statistics homepage" urlStringFormat="https://www.ssb.no/en/{0}" />
+      </relationalGroup>
+     ... 
+
+```
+
+When the api finds this META-ID "STATISTICS:aku", on table level, it creates
+```
+"relation": "statistics-homepage"
+"href": "https://www.ssb.no/en/aku"
+"label": "Statistics homepage"
+"type": "text/html"
+```
+for an english request.
+
+This is done by looping all metasystems for the attachment level and see if the META-ID starts with the id of the metasystem. If so, output is produced.
+The rest of the META-ID after the id of the metasystem is considered to be arguments.
+This matching mechanism allows for colons in the ids of the metasystems. 
+
+Here is a full metaid.config:
+```
+<?xml version="1.0"?>
+<metaId>
+  <onTable>
+    <metaSystem id="STATISTICS">
+      <relationalGroup relation="statistics-homepage" type="text/html">
+        <link pxLang="no" labelStringFormat="Statistikkens hjemmeside" urlStringFormat="https://www.ssb.no/{0}" />
+        <link pxLang="en" labelStringFormat="Statistics homepage" urlStringFormat="https://www.ssb.no/en/{0}" />
+      </relationalGroup>
+      <relationalGroup relation="about-statistics" type="text/html">
+         <link pxLang="no" labelStringFormat="Om statistikken" urlStringFormat="https://www.ssb.no/{0}#om-statistikken" />
+         <link pxLang="en" labelStringFormat="About the statistics" urlStringFormat="https://www.ssb.no/en/{0}#om-statistikken" />
+      </relationalGroup>
+    </metaSystem> 
+  </onTable>
+  <onVariable>
+    <metaSystem id="urn:ssb:classification:klass">
+       <relationalGroup relation="definition-classification" type="text/html">   
+         <link pxLang="no" labelStringFormat="Klassifikasjon for {0}." urlStringFormat="https://www.ssb.no/klass/klassifikasjoner/{0}" />
+         <link pxLang="en" labelStringFormat="Classification for {0}." urlStringFormat="https://www.ssb.no/en/klass/klassifikasjoner/{0}" />
+       </relationalGroup>  
+    </metaSystem>
+    <metaSystem id="urn:ssb:conceptvariable:vardok">
+      <relationalGroup relation="definition-classification" type="text/html">   
+         <link pxLang="no" labelStringFormat="Definisjon av {0}." urlStringFormat="https://www.ssb.no/a/metadata/conceptvariable/vardok/{0}/nb" />
+         <link pxLang="en" labelStringFormat="Definition of {0}." urlStringFormat="https://www.ssb.no/a/metadata/conceptvariable/vardok/{0}/en" />
+      </relationalGroup>
+    </metaSystem>
+  </onVariable>
+  <onValue>
+    <metaSystem id="urn:ssb:conceptvariable:vardok">
+      <relationalGroup relation="definition-value" type="text/html">
+        <link pxLang="no" labelStringFormat="Definisjon av {1} for vaiabel {0}." urlStringFormat="https://www.ssb.no/a/metadata/conceptvariable/vardok/{0}/nb" />
+        <link pxLang="en" labelStringFormat="Definition of {1} for vaiable {0}." urlStringFormat="https://www.ssb.no/a/metadata/conceptvariable/vardok/{0}/en" />
+      </relationalGroup>
+    </metaSystem>
+    <metaSystem id="urn:ssb:contextvariable:common">
+      <relationalGroup relation="definition-value" type="text/html">
+        <link pxLang="no" labelStringFormat="Definisjon av {1} (Kostra)." urlStringFormat="https://www.ssb.no/kompis/statbank/?id={0}&amp;ver={1}&amp;val={2}" />
+        <link pxLang="en" labelStringFormat="Definition of {1} (Kostra)." urlStringFormat="https://www.ssb.no/kompis/statbank/?id={0}&amp;ver={1}&amp;val={2}" />
+      </relationalGroup>  
+    </metaSystem>
+  </onValue>
+</metaId>
+
+``` 
+Note: 
+* The metaSystem STATISTICS creates 2 links per language. 
+* The last metaSystem on value does not use the name of the variable, only the name of the value.
+
+## In the gui
+The usecase is to provide content in pxweb2gui for the areas shown in Figma_infomation_defs.png
+
+  ![Information pane in figma](Figma_infomation_defs.png?raw=true)
+
+
+
+Figma_infomation_defs.png: 
+  to get content for "area-1" , links with relation="statistics-homepage" on root is used
+  to get content for "area-2" , links with relation="about-statistics" on root
+  to get content for "area-3" , loop variables and look for relations starting with "definition-"
+
+
@@ -24,6 +24,7 @@ nav:
       - Other:
           - Try PxWeb 2 with Docker: PxWeb2/documentation/docker.md
           - Changes in savedquery usage: Other/changes-in-savedquery-usage.md
+          - Links from a dataset (metaid): Other/metaid.md
           - PX file format 2013: https://github.com/PxTools/PxFileFormat/blob/main/px-file-format.md
 
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