---
title: "C Plug-In Callback Interface"
slug: "c-plug-in-callback-interface"
updated: 2020-04-16T21:25:46Z
published: 2020-04-16T21:25:46Z
canonical: "onpremises.webtrends.help/c-plug-in-callback-interface"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://onpremises.webtrends.help/llms.txt
> Use this file to discover all available pages before exploring further.

# C Plug-In Callback Interface

All plug-ins have access to the `ResolveName` and `ApplyTranslation` callback functions. The log file fields that can be accessed using the `ResolveName` function and the modifications that can be performed using the `ApplyTranslation` function depend on the object that the plug-in works with.

The following sections describe the `ResolveName` and `ApplyTranslation` functions which are defined in `translate.h` file.

## ResolveName

Your plug-in can use the `ResolveName` callback function to request the value of a particular log file object from Webtrends.

#### Parameters

**`lpszName`** This parameter indicates which part of the log file record the plug-in wants Webtrends to return. The argument `lpszName` may contain multiple names separated by commas. The first one that resolves is returned. For more information about valid values, see “Parameter Values,” below.

**`lpDetails`** The opaque pointer that is passed to the plug-in’s `xltTranslate`, `XltTranslateVisitorHit`, and `xltTranslateVisitorSession` callback functions.

**`lpsrResult`** The string returned to the plug-in from Webtrends. Because the value may or may not be null-terminated, you should only refer to `lpsrResult->GetLength()` characters starting at `lpsrResult->GetData()`.

#### Return Values

**`XLTOK`** The function returns `XLTOK` if the value identified by the `lpszName` parameter is returned.

**`XLTERR`** The function returns `XLTERR` if the value identified by the `lpszName` parameter is not returned.

#### Function Specification

```
int ResolveName (const char *lpszName, void *lpDetails, StringRef
*lpsrResult);
```

## ApplyTranslation

The `ApplyTranslation` callback function modifies the value of the object requested by the `ResolveName` function and sends it back to Webtrends to use in the analysis.

#### Arguments

**`lpDetails`** The opaque pointer that is passed to the plug-in’s `xltTranslate`, `XltTranslateVisitorHit`, and `xltTranslateVisitorSession` functions.

**`lpszName`** The portion of the log file record to act upon.

**`lpszAction`** The action to take. You can `replace` the value or `append` to the existing value.

**`lpszNewString`** The value that you want to replace or append to the log file object specified.

#### Return Values

The `ApplyTranslation` function returns `true` if the `lpszName` is resolved; `false` if the name cannot be resolved.

#### Function Specification

```
int ApplyTranslation(void *lpDetails, const char* lpszName, const char* 
lpszAction, const char* lpszNewString);
```

## Parameter Values

The following tables show the possible values of `lpszName`, the possible values of `lpszAction`, and the maximum replacement string length. The values of `lpszName` (object parameter name) and `lpszAction`(action parameter name) are not case-sensitive.

#### xltTranslate Parameters

You can use the following parameter values with the `xltTranslate()` function.

| lpszName Parameters | ResolveName() | ApplyTranslation() | Maximum string replacement length | lpszAction Parameters | Valid for Basic Analysis Profiles |
| --- | --- | --- | --- | --- | --- |
| `"url"` | Yes | Yes |  | `"replace"` | Yes |
| `"urlstem"` | Yes | Yes |  | `"replace"` | Yes |
| `"urlandparams"` | Yes | Yes |  | `"replace"` | Yes |
| `"params"` | Yes | Yes |  | Entire parameter string `"replace"` or `"append"` | Yes |
| `"cookie"` | Yes | Yes |  | Entire cookie string `"replace"` | Yes |
| `"authuser"` | Yes | Yes |  | `"replace"` | Yes |
| `"referer"` | Yes | Yes |  | `"replace"` | Yes |
| `"referrer"` | Yes | Yes |  | `"replace"` | Yes |
| `"referrer-domain"` | Yes | No |  | `"replace"` | No |
| `"datetime"` | Yes | Yes |  | `"replace"` | Yes |
| `"host"` | Yes | Yes | Less than 103 characters | `"replace"` | Yes |
| `"rawlogline"` | Yes | No |  | `"replace"` | No |
| `"sessionid"` | Yes | Yes | Less than 128 characters | `"replace"` | No |
| `"method"` | Yes | Yes |  | `"replace"` | Yes |
| `"status"` | Yes | Yes |  | `"replace"` | Yes |
| `"agent"` | Yes | Yes |  | `"replace"` | Yes |
| `"client"` | Yes | Yes |  | `"replace"` | Yes |
| `"duration"` | Yes | Yes |  | `"replace"` | No |
| `"protocol"` | Yes | Yes |  | `"replace"` | No |
| `"oneparam:name"` | Yes | Yes |  | Specify individual parameter name for *`name`* `"replace"` | Yes |
| `"onecookie:name"` | Yes | Yes |  | Specify individual cookie name for *`name`* `"replace"` | Yes |
| `"delparam:name"` | No | Yes |  | Specify individual parameter name for *`name`* `"replace"` | Yes |
| `"delcookie:name"` | No | Yes |  | Specify individual cookie name for *`name`* `"replace"` | Yes |
| `"search-engine"` | Yes | No |  | `"replace"` | No |
| `"search-phrase"` | Yes | No |  | `"replace"` | No |

#### xltTranslateVisitorHit Parameters

The following parameters are valid only for use within the `xltTranslateVisitorHit()` method.

| lpszName Parameters | ResolveName() | ApplyTranslation() | lpszAction Parameters |
| --- | --- | --- | --- |
| `"vr-oneparam:name"` | Yes | Yes | Specify individual parameter name for *`name`* `"replace"` |
| `"vr-onecookie:name"` | Yes | Yes | Specify individual cookie name for *`name`* `"replace"` |
| `"vr-delparam:name"` | No | Yes | Specify individual parameter name for *`name`*`"replace"` |
| `"vr-delcookie:name"` | No | Yes | Specify individual cookie name for *`name`* `"replace"` |

#### xltTranslateVisitorSession Parameters

The following parameters are only valid for use within the `xltTranslateVisitorSession()` function.

| lpszName Parameters | ResolveName() | TranslateName() | lpszAction Parameters |
| --- | --- | --- | --- |
| `"datetime"` | Yes | No | Time the session occurred |
| `"visittime"` | Yes | No | Number of seconds attributed to the session |