Can't pass XML string

[davenquinn]

I'm using node-mapnik 3.6.0 and generate a mapnik XML file shown below using carto

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE Map[]>
<Map srs="+init=epsg:3857">


<Style name="terrain" filter-mode="first">
  <Rule>
    <LineSymbolizer stroke="#000000" stroke-width="2" />
  </Rule>
</Style>
<Layer name="terrain"
  srs="+init=epsg:3857">
    <StyleName>terrain</StyleName>
    <Datasource>
       <Parameter name="dbname"><![CDATA[Naukluft]]></Parameter>
       <Parameter name="geometry_field"><![CDATA[geometry]]></Parameter>
       <Parameter name="host"><![CDATA[localhost]]></Parameter>
       <Parameter name="table"><![CDATA[(SELECT id, vertical_geom AS geometry FROM cross_section.section) AS a]]></Parameter>
       <Parameter name="type"><![CDATA[postgis]]></Parameter>
       <Parameter name="srid"><![CDATA[null]]></Parameter>
    </Datasource>
  </Layer>

</Map>

Config (in coffeescript):

strata = tilestrata()

strata
  .layer("geology")
    .route '[email protected]'
    .use tileStrataMapnik {xml: <xml string above>, tileSize: 512, scale: 2 }

strata.listen(39805)

Traceback:

/Users/Daven/Development/Naukluft/versioned/node_modules/tilestrata/lib/TileServer.js:519
	var callback = function(err) { if (err) throw err; };
	                                        ^

Error: Unable to initialize "geology" layer: "Path must be a string. Received undefined"
    at /Users/Daven/Development/Naukluft/versioned/node_modules/tilestrata/lib/TileServer.js:106:19
    at /Users/Daven/Development/Naukluft/versioned/node_modules/tilestrata/node_modules/async/lib/async.js:52:16
    at done (/Users/Daven/Development/Naukluft/versioned/node_modules/tilestrata/node_modules/async/lib/async.js:243:17)
    at /Users/Daven/Development/Naukluft/versioned/node_modules/tilestrata/node_modules/async/lib/async.js:44:16
    at Immediate._onImmediate (/Users/Daven/Development/Naukluft/versioned/node_modules/tilestrata/lib/TileRequestHandler.js:125:4)
    at runCallback (timers.js:781:20)
    at tryOnImmediate (timers.js:743:5)
    at processImmediate [as _immediateCallback] (timers.js:714:5)

When I write the file out and refer to the pathname instead, everything works as expected.

[brianreavis]

Thanks for all this! These lines of tilelive-mapnik seem to be the culprit: https://github.com/mapbox/tilelive-mapnik/blob/v0.6.18/lib/mapnik_backend.js#L208-L211 (which apparently silently fail on old versions of node?).

Could you try using pathname in conjunction with xml (setting it to the path of the xml, as if it were to exist on disk)? This way mapnik will know the base directory. Assuming this works, this should be documented in the readme and I can take care of that.

[davenquinn]

Hi Brian,

I just tried this, setting pathname: "style.xml" which is a non-existent path name, along with passing xml. This works fine (I guess I would need to specify an existing directory name if I had relative paths in my config).

Thanks for the quick response!