# Extendconfiguration

Extendconfiguration allows to configure some options of the server inside a `<host>` tag. (This extension is available starting from Ocsigen ≥ 1\.2)


## Loading the extension

To use that extension, load OCamlfind package `ocsigenserver.ext.extendconfiguration`, either from your Dune file (if you are using static linking), or from the configuration file:

```
<extension findlib-package="ocsigenserver.ext.extendconfiguration"/>
```

## Options

This section describes the configuration file options. If you are building a statically linked executable without configuration file, use the corresponding functions from module [`Extendconfiguration`](./Extendconfiguration.md).


### Following symlinks

For extensions that access files on the filesystem ([staticmod](./staticmod.md),...), you can decide whether symlinks should be followed or not, using the tag

```
<followsymlinks value="VAL" />
```
where `VAL` can be:

- `never` entirely disallows following symlinks.
- `always` always follows symlinks (more efficient). Note that this setting is not permitted in userconf files
- `ownermatch` symlinks are followed only if the owner of the symlink and of the target coincide. (Default value)
Notice that staticmod partially overrides this setting when it is not used in a userconf file. When used with the syntax `<static dir="dir" />`, the checks start only after the directory `dir`. In regexp mode, the checks only start after the value given by the `root` attribute. See the documentation of [staticmod](./staticmod.md) for details.


### Hiding or forbidding local files

Again for extensions that send local files, you can selectively disallow sending some files. The syntax is as such:

```
<hidefile>
  <extension ext="php" />
  <extension ext="cgi" />
  <file file=".htaccess" />
  <regexp regexp=".*hidden_file.*" /> <!-- End the regexp with $ to match the full file name -->
</hidefile>
```
Using the tag `hidefile` results in 404 error codes. To have 403 errors, use `forbidfile` instead.


### Index of directories

When the user requests access to a directory of the filesystem, Ocsigen can automatically try to find an index file. This is done through the following option

```
<defaultindex>
  <index>index1</index>
  <index>index2</index>
</defaultindex>
```
Ocsigen serves the first file (according to the order given by the index tags) that exists.


### List the content of directories

If you want to list the content of a directory that does not contain an index file, use the tag

```
<listdirs value="true" />
```
You can also deactivate this option with `value="false"` instead.


### Charset

The charset of the text files that are sent by the server can be set using the tag

```
<charset default="utf-8">
  <extension ext='txt' value="iso8859-15" />
  <file file="bla.text" value="iso8859-15" />
  <regexp regexp=".*text.*"  value="iso8859-15" />
</charset>
```
This sets the default charset for text files to `utf8`, while files whose extension are `txt`, or that are named `bla.text`, or whose name contains `text` are sent as `iso8859-15`.

Multiple extension tags can be specified. Both the default attribute and extension tags are optional. Extension tags are cumulative between the various sites.


### Content-type

The content-type for the files sent by the server can be specified using the tag

```
<contenttype default="application/octet-stream">
  <extension ext='txt' value="text/plain" />
  <file file="bla.text" value="text/plain" />
  <regexp regexp=".*text.*"  value="text/plain" />
</contenttype>
```
The options are similar to the ones for the `charset` tag.


### File uploading

*From Ocsigen ≥ 1\.3*

You can specify the directory in which the files stored in POST requests are uploaded, as well as the maximum size for these files. The two options are named `uploaddir` and `maxuploadfilesize`:

```
<uploaddir>/tmp</uploaddir>
<maxuploadfilesize>1MB</maxuploadfilesize>
```
The arguments are the same as for the global corresponding options ; see the [configuration](./config.md#upload) page for details. In order to disallow uploading for a specific host or site, use an empty path: `<uploaddir></uploaddir>`.

*Warning*

POST arguments (including sent files) are read once and for all, by the first extension that attempts to decode the POST parameters. This means that the POST-uploaded files are stored *according to the settings local to this first extension*. Changing the `uploaddir` and `maxuploadfilesize` options later will have no effect; plan accordingly when you write your `ocsigen.conf` file. Currently the only extension supplied with Ocsigen that reads POST data is Eliom.


## Visibility

The options above are visible until the end of the \<site\> tag they are part of.