# Mount and Bind Configuration in Apache, Nginx, IIS, and Acequia

## Overview

Web servers expose files and services by mapping URL paths to local or remote resources.
These mappings—called *mount points*—are configured differently in Apache, Nginx, and IIS.

Acequia, which uses WebDAV as a central protocol, needs a mount and bind configuration
that is portable, declarative, and browser-friendly. This document reviews existing web
server configs and proposes a JSON-based config file format for Acequia.

---

## Apache (`httpd.conf`)

Apache uses directives to mount URL paths to filesystem directories:

- `DocumentRoot` defines the root directory for a virtual host.
- `Alias` maps specific URL paths to other directories.
- `<Directory>` configures access and behavior for mounted paths.

### Example

```
Alias /images/ "/data/media/images/"
<Directory "/data/media/images/">
    Options Indexes FollowSymLinks
    AllowOverride None
    Require all granted
</Directory>
```

Apache does not support true resource-level BIND semantics. However, similar behavior
can be mimicked using filesystem-level symlinks.

---

## Nginx (`nginx.conf`)

Nginx uses a block-structured config format with the `location` directive to define mount behavior:

- `root` appends the requested URI to the root path.
- `alias` replaces the URI prefix with a new path directly.

### Example

```
server {
    listen 80;
    server_name example.com;

    location /images/ {
        alias /data/media/images/;
        autoindex on;
    }
}
```

Like Apache, Nginx does not support BIND semantics out of the box, but URL rewriting
and symbolic links can achieve similar outcomes.

---

## IIS (`web.config`)

IIS uses *virtual directories* to map URL paths to filesystem paths.

This is configured via the IIS Manager GUI or in `web.config`:

### Example

```xml
<configuration>
  <system.applicationHost>
    <sites>
      <site name="MySite">
        <virtualDirectory path="/images" physicalPath="D:\media\images" />
      </site>
    </sites>
  </system.applicationHost>
</configuration>
```

IIS treats mount points as isolated logical folders, and does not natively support binding
multiple paths to the same resource identity.

---

## Acequia (`acequia.conf.json`)

Acequia proposes a JSON-based configuration format to define mount points and
resource bindings across decentralized nodes. This file can live in the root directory
of a data volume or be advertised at a well-known path (e.g. `.well-known/acequia.conf.json`).

### Example

```json
{
  "mounts": [
    {
      "mountPath": "/photos",
      "target": "file:///Volumes/Media/Photos",
      "type": "local",
      "readOnly": true,
      "label": "Media Drive - Photos"
    },
    {
      "mountPath": "/docs/reports",
      "target": "https://example.org/webdav/reports/",
      "type": "webdav",
      "auth": {
        "method": "basic",
        "username": "user",
        "password": "env:WEBDAV_PASS"
      }
    },
    {
      "mountPath": "/datasets",
      "target": "ipfs://QmSomeCID12345",
      "type": "ipfs",
      "readOnly": true
    }
  ]
}
```

This format supports:
- Local and remote targets
- Multiple backends (file, WebDAV, IPFS, etc.)
- Optional authentication
- BIND-like semantics by allowing multiple `mountPath`s to reference the same `target`

---

## Conclusion

Apache, Nginx, and IIS each support static mount point configuration tied to the local filesystem.
None of them natively support BIND operations as defined in RFC 5842.

Acequia introduces a portable JSON configuration file, `acequia.conf.json`, that extends
the idea of mount points into a decentralized, multi-protocol WebDAV-based system.