# Limitations, Restrictions, and Known Issues

## All Cloudant SDKs

### Path elements containing the `+` character

Path elements containing the `+` character in the SDKs are not interoperable with:
* Cloudant 
* Apache CouchDB versions older than 3.2.0
* Apache CouchDB versions 3.2.0 or newer with the setting `decode_plus_to_space = true`

This is because standard URL encoding libraries following the [RFC3986 URI specification](https://tools.ietf.org/html/rfc3986#section-3.3) do not encode the `+` character in path elements.
* It is possible to workaround for document names with a `+` in the ID (e.g. `docidwith+char`) by using:
    * For reading: use the `post` all docs operation and the `key` or `keys` parameter with a value of the document ID including the `+`.
    * For writing: use the `post` document operation or `post` bulk docs operation with the value of the document ID including the `+`.
* There is no pre-encoding workaround because the result is a double encoding e.g. using `%2b` in the path element ends up being double encoded as `%252b`.

### Views

#### Objects as keys

Using JSON objects as keys (e.g. `start_key`, `end_key`, `key`, `keys`)
can cause inconsistent results because the ordering of the members of the JSON
object after serialization is not guaranteed.

### Documents

#### Attachments

The `atts_since` parameter is not supported when retrieving a document.
The workaround is to call `POST /{db}/_bulk_get` using the `atts_since` field under the `docs` request body. See the [alternative example request for `atts_since` using the `/_bulk_get` endpoint](https://cloud.ibm.com/apidocs/cloudant#postbulkget) in our API Docs.
Example JSON request body:
```json
{
  "docs": [{"id": "order00058", "atts_since": "1-99b02e08da151943c2dcb40090160bb8"}]
}
```

#### Open revisions

The `open_revs` parameter is not supported when retrieving a document.
If you want to retrieve documents with all leaf revisions (`open_revs=all`), the workaround is to call `POST /{db}/_bulk_get` using the `id` field within the `docs` array request body.
See the [alternative example request for `open_revs=all` using the `/_bulk_get` endpoint](https://cloud.ibm.com/apidocs/cloudant#postbulkget) in our API Docs.
Example JSON request body:
```json
{
  "docs": [{"id": "order00067"}]
}
```

If you want to retrieve documents of specified leaf revisions (e.g. `open_revs=["3-917fa2381192822767f010b95b45325b", "4-a5be949eeb7296747cc271766e9a498b"]`), the workaround is to call `POST /{db}/_bulk_get` using the same `id` value for each unique `rev` value within of the `docs` array request body.
See the [default example request using the `/_bulk_get` endpoint](https://cloud.ibm.com/apidocs/cloudant#postbulkget) in our API Docs.
Example JSON request body:
```json
{
  "docs": [
    {
      "id": "order00067",
      "rev": "3-917fa2381192822767f010b95b45325b"
    },
    {
      "id": "order00067",
      "rev": "4-a5be949eeb7296747cc271766e9a498b"
    }
  ]
}
```

### Compression

* Manually setting an `Accept-Encoding` header on requests will disable the transparent gzip decompression of response bodies from the server.
* Manually setting a `Content-Encoding` header on requests will disable the transparent gzip compression of request bodies to the server.

### Changes feed

#### Filter functions

The SDK does not support passing user-defined query or body parameters in `_changes` requests for dynamic filter functions in design documents. 
The workaround and recommended option is to use a `selector` type filter.
For example, if you are using a `_changes` request like `/{db}/_changes?filter=myDdoc/byName&name=Jane` with a filter function like:
```javascript
function(doc, req) {
    if (doc.name !== req.query.name) {
        return false;
    }
    return true; 
}
```
It can be replaced with a request using a selector filter:
```js
const service = CloudantV1.newInstance({});

service.postChanges({
  db: 'example',
  filter: '_selector',
  selector: {"name": "Jane"}
}).then(response => { ... });
```


## Cloudant SDK for Node.js
<!-- KNOWN_ISSUES specific to Node -->
### Disabling request body compression

Some issues with older server versions can be worked around by disabling
compression of request bodies. This is an example of how to do that.

```js
import { CloudantV1 } from '@ibm-cloud/cloudant';
const client = CloudantV1.newInstance({ serviceName: 'YOUR_SERVICE_NAME' });
client.setEnableGzipCompression(false);
...
```