Named URIs allow to identify DataSources and pass additional information
A Named URI consists of
As a refresher, a URI is made up of the following components (inspired by https://docs.gomplate.ca/datasources/)
foo://userinfo@example.com:8042/over/there?name=ferret#nose \_/ \_______________________/\_________/ \_________/ \__/ | | | | | scheme authority path query fragment
For our purposes, the scheme and the path components are especially important, though the other components are used by certain data sources for particular purposes.
| Component | Purpose |
|---|---|
| scheme | All data sources require a scheme (except for file when using relative paths) |
| authority | Used only by remote data sources, and can be omitted in some of those cases. |
| path | Can be omitted, but usually used as the basis of the locator for the datasource. |
| query | Used mainly for HTTP and HTTPS URLs |
| fragment | Used rarely for providing additional attributes, e.g. mimeType of charset |
The following Named URI loads a “user.csv” and the data source is available as my_users
freemarker-generator -t freemarker-generator/info.ftl my_users=examples/data/csv/user.csv FreeMarker Generator DataSources ------------------------------------------------------------------------------ [#1]: name=my_users, group=default, fileName=my_users mimeType=text/csv, charset=UTF-8, length=376 Bytes URI : file:/Users/sgoeschl/work/github/apache/freemarker-generator/freemarker-generator-cli/target/appassembler/examples/data/csv/user.csv
A Named URI allows to pass additional information as part of the fragment, e.g. the charset of the text file
freemarker-generator -t freemarker-generator/info.ftl my_users=examples/data/csv/user.csv#charset=UTF-16 FreeMarker Generator DataSources ------------------------------------------------------------------------------ [#1]: name=my_users, group=default, fileName=my_users mimeType=text/csv, charset=UTF-16, length=376 Bytes URI : file:/Users/sgoeschl/work/github/apache/freemarker-generator/freemarker-generator-cli/target/appassembler/examples/data/csv/user.csv
In addition to the simplified file syntax full URIs can be used
freemarker-generator -t freemarker-generator/info.ftl http://google.com?foo=bar FreeMarker Generator DataSources ------------------------------------------------------------------------------ [#1]: name=http://google.com?foo=bar, group=default, fileName=google.com?foo=bar mimeType=text/html, charset=ISO-8859-1, length=-1 Bytes URI : http://google.com?foo=bar
and also combined with a name
freemarker-generator -t freemarker-generator/info.ftl page=http://google.com\?foo\=bar FreeMarker Generator DataSources ------------------------------------------------------------------------------ [#1]: name=page, group=default, fileName=page mimeType=text/html, charset=ISO-8859-1, length=-1 Bytes URI : http://google.com?foo=bar