Audit usage of the searchPosts API (#29909)

* Audit calls to searchPosts API

* Update server/public/model/post_search_results.go

Co-authored-by: Ben Schumacher <ben.schumacher@mattermost.com>

* Update server/public/model/post_search_results.go

* Update server/public/model/post_search_results.go

---------

Co-authored-by: Ben Schumacher <ben.schumacher@mattermost.com>
Co-authored-by: Mattermost Build <build@mattermost.com>

server/channels/api4/post.go

@@ -790,6 +790,10 @@ func searchPosts(c *Context, w http.ResponseWriter, r *http.Request, teamId stri
 		includeDeletedChannels = *params.IncludeDeletedChannels
 	}
 
+	auditRec := c.MakeAuditRecord("searchPosts", audit.Fail)
+	defer c.LogAuditRecWithLevel(auditRec, app.LevelAPI)
+	audit.AddEventParameterAuditable(auditRec, "search_params", params)
+
 	startTime := time.Now()
 
 	results, err := c.App.SearchPostsForUser(c.AppContext, terms, c.AppContext.Session().UserId, teamId, isOrSearch, includeDeletedChannels, timeZoneOffset, page, perPage)
@@ -814,6 +818,8 @@ func searchPosts(c *Context, w http.ResponseWriter, r *http.Request, teamId stri
 	}
 
 	results = model.MakePostSearchResults(clientPostList, results.Matches)
+	audit.AddEventParameterAuditable(auditRec, "search_results", results)
+	auditRec.Success()
 
 	w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
 	if err := results.EncodeJSON(w); err != nil {

server/public/model/post.go

@@ -207,6 +207,21 @@ type SearchParameter struct {
 	IncludeDeletedChannels *bool   `json:"include_deleted_channels"`
 }
 
+func (sp SearchParameter) Auditable() map[string]interface{} {
+	return map[string]interface{}{
+		"terms":                    sp.Terms,
+		"is_or_search":             sp.IsOrSearch,
+		"time_zone_offset":         sp.TimeZoneOffset,
+		"page":                     sp.Page,
+		"per_page":                 sp.PerPage,
+		"include_deleted_channels": sp.IncludeDeletedChannels,
+	}
+}
+
+func (sp SearchParameter) LogClone() any {
+	return sp.Auditable()
+}
+
 type AnalyticsPostCountsOptions struct {
 	TeamId        string
 	BotsOnly      bool

server/public/model/post_search_results.go

@@ -39,3 +39,18 @@ func (o *PostSearchResults) ForPlugin() *PostSearchResults {
 	plCopy.PostList = plCopy.PostList.ForPlugin()
 	return &plCopy
 }
+
+func (o *PostSearchResults) Auditable() map[string]interface{} {
+	var numResults int
+	var hasNext bool
+
+	if o.PostList != nil {
+		numResults = len(o.PostList.Posts)
+		hasNext = SafeDereference(o.PostList.HasNext)
+	}
+
+	return map[string]any{
+		"num_results": numResults,
+		"has_next":    hasNext,
+	}
+}