title: SourceObject
---
summary: The basic interface of all source objects.
---
module: lektor.sourceobj
---
type: class
---
body:

Source objects is the common interface for all things that come out of the
database.  There are two types of source objects:

* [Records :ref](../record/) which are pages and attachments from the
  `contents/` folder.
* [Assets :ref](../asset/) which are files and directories from the
  `assets/` folder.

Whatever object you have in hand that comes from the database, they will
at least provide a minimal useful set of API methods and properties.

Plugins can subclass source objects to come up with their own source
objects if needed.  In addition to that there is a special source object
called the `VirtualSourceObject` which is more useful for plugin usage.

## Virtual Source Objects

Most plugins will not have source objects that actually originate on the
file system.  This means that their "source" is entirely virtual.  Because
this is a very common situation there is a base class, the
`VirtualSourceObject` which plugins can subclass.  The constructor takes one
argument which is the source record the virtual source lives below.  Virtual
sources are separated from the records they belong to with an at sign (`@`)
in the path.  The part after the at sign is called the “virtual path”.

For instance in the below example the canonical path for the object would be
the record's path + `@source`.  So if the record was `/hello` then the
path would be `/hello@source`.  The true base record it belongs to can be
referenced from the [record :ref](record/) property.

```python
from lektor.sourceobj import VirtualSourceObject
from lektor.utils import build_url

class Source(VirtualSourceObject):

    @property
    def path(self):
        return self.record.path + '@source'

    @property
    def source_content(self):
        with open(self.record.source_filename) as f:
            return f.read().decode('utf-8')

    @property
    def url_path(self):
        return build_url([self.record.url_path, 'source.txt'])
```

For more information see [add-build-program
:ref](../../environment/add-build-program/) as well as
[virtualpathresolver :ref](../../environment/virtualpathresolver/).
