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Server Reference

This is the documentation for the Go github.com/mattermost/mattermost-server/plugin package. It can also be found on GoDoc

The plugin package is used by Mattermost server plugins written in go. It also enables the Mattermost server to manage and interact with the running plugin environment.

Note that this package exports a large number of types prefixed with Z_. These are public only to allow their use with Hashicorp's go-plugin (and net/rpc). Do not use these directly.

API 

The API can be used to retrieve data or perform actions on behalf of the plugin. Most methods have direct counterparts in the REST API and very similar behavior.

Plugins obtain access to the API by embedding MattermostPlugin and accessing the API member directly.

Hooks 

Hooks describes the methods a plugin may implement to automatically receive the corresponding event.

A plugin only need implement the hooks it cares about. The MattermostPlugin provides some default implementations for convenience but may be overridden.

Examples


API

(API) LoadPluginConfiguration 

LoadPluginConfiguration(dest interface{}) error

LoadPluginConfiguration loads the plugin's configuration. dest should be a pointer to a struct that the configuration JSON can be unmarshalled to.

(API) RegisterCommand 

RegisterCommand(command *model.Command) error

RegisterCommand registers a custom slash command. When the command is triggered, your plugin can fulfill it via the ExecuteCommand hook.

(API) UnregisterCommand 

UnregisterCommand(teamId, trigger string) error

UnregisterCommand unregisters a command previously registered via RegisterCommand.

(API) GetSession 

GetSession(sessionId string) (*model.Session, *model.AppError)

GetSession returns the session object for the Session ID

(API) GetConfig 

GetConfig() *model.Config

GetConfig fetches the currently persisted config

(API) SaveConfig 

SaveConfig(config *model.Config) *model.AppError

SaveConfig sets the given config and persists the changes

(API) GetPluginConfig 

GetPluginConfig() map[string]interface{}

GetPluginConfig fetches the currently persisted config of plugin

Minimum server version: 5.6

(API) SavePluginConfig 

SavePluginConfig(config map[string]interface{}) *model.AppError

SavePluginConfig sets the given config for plugin and persists the changes

Minimum server version: 5.6

(API) GetServerVersion 

GetServerVersion() string

GetServerVersion return the current Mattermost server version

Minimum server version: 5.4

(API) CreateUser 

CreateUser(user *model.User) (*model.User, *model.AppError)

CreateUser creates a user.

(API) DeleteUser 

DeleteUser(userId string) *model.AppError

DeleteUser deletes a user.

(API) GetUser 

GetUser(userId string) (*model.User, *model.AppError)

GetUser gets a user.

(API) GetUserByEmail 

GetUserByEmail(email string) (*model.User, *model.AppError)

GetUserByEmail gets a user by their email address.

(API) GetUserByUsername 

GetUserByUsername(name string) (*model.User, *model.AppError)

GetUserByUsername gets a user by their username.

(API) GetUsersByUsernames 

GetUsersByUsernames(usernames []string) ([]*model.User, *model.AppError)

GetUsersByUsernames gets users by their usernames.

Minimum server version: 5.6

(API) GetUsersInTeam 

GetUsersInTeam(teamId string, page int, perPage int) ([]*model.User, *model.AppError)

GetUsersInTeam gets users in team.

Minimum server version: 5.6

(API) GetTeamIcon 

GetTeamIcon(teamId string) ([]byte, *model.AppError)

GetTeamIcon gets the team icon.

Minimum server version: 5.6

(API) SetTeamIcon 

SetTeamIcon(teamId string, data []byte) *model.AppError

SetTeamIcon sets the team icon.

Minimum server version: 5.6

(API) RemoveTeamIcon 

RemoveTeamIcon(teamId string) *model.AppError

RemoveTeamIcon removes the team icon.

Minimum server version: 5.6

(API) UpdateUser 

UpdateUser(user *model.User) (*model.User, *model.AppError)

UpdateUser updates a user.

(API) GetUserStatus 

GetUserStatus(userId string) (*model.Status, *model.AppError)

GetUserStatus will get a user's status.

(API) GetUserStatusesByIds 

GetUserStatusesByIds(userIds []string) ([]*model.Status, *model.AppError)

GetUserStatusesByIds will return a list of user statuses based on the provided slice of user IDs.

(API) UpdateUserStatus 

UpdateUserStatus(userId, status string) (*model.Status, *model.AppError)

UpdateUserStatus will set a user's status until the user, or another integration/plugin, sets it back to online. The status parameter can be: "online", "away", "dnd", or "offline".

(API) UpdateUserActive 

UpdateUserActive(userId string, active bool) *model.AppError

UpdateUserActive deactivates or reactivates an user.

Minimum server version: 5.8

(API) GetUsersInChannel 

GetUsersInChannel(channelId, sortBy string, page, perPage int) ([]*model.User, *model.AppError)

GetUsersInChannel returns a page of users in a channel. Page counting starts at 0. The sortBy parameter can be: "username" or "status".

Minimum server version: 5.6

(API) GetLDAPUserAttributes 

GetLDAPUserAttributes(userId string, attributes []string) (map[string]string, *model.AppError)

GetLDAPUserAttributes will return LDAP attributes for a user. The attributes parameter should be a list of attributes to pull. Returns a map with attribute names as keys and the user's attributes as values. Requires an enterprise license, LDAP to be configured and for the user to use LDAP as an authentication method.

Minimum server version: 5.3

(API) CreateTeam 

CreateTeam(team *model.Team) (*model.Team, *model.AppError)

CreateTeam creates a team.

(API) DeleteTeam 

DeleteTeam(teamId string) *model.AppError

DeleteTeam deletes a team.

(API) GetTeams 

GetTeams() ([]*model.Team, *model.AppError)

GetTeam gets all teams.

(API) GetTeam 

GetTeam(teamId string) (*model.Team, *model.AppError)

GetTeam gets a team.

(API) GetTeamByName 

GetTeamByName(name string) (*model.Team, *model.AppError)

GetTeamByName gets a team by its name.

(API) GetTeamsUnreadForUser 

GetTeamsUnreadForUser(userId string) ([]*model.TeamUnread, *model.AppError)

GetTeamsUnreadForUser gets the unread message and mention counts for each team to which the given user belongs.

Minimum server version: 5.6

(API) UpdateTeam 

UpdateTeam(team *model.Team) (*model.Team, *model.AppError)

UpdateTeam updates a team.

(API) GetTeamsForUser 

GetTeamsForUser(userId string) ([]*model.Team, *model.AppError)

GetTeamsForUser returns list of teams of given user ID.

Minimum server version: 5.6

(API) CreateTeamMember 

CreateTeamMember(teamId, userId string) (*model.TeamMember, *model.AppError)

CreateTeamMember creates a team membership.

(API) CreateTeamMembers 

CreateTeamMembers(teamId string, userIds []string, requestorId string) ([]*model.TeamMember, *model.AppError)

CreateTeamMember creates a team membership for all provided user ids.

(API) DeleteTeamMember 

DeleteTeamMember(teamId, userId, requestorId string) *model.AppError

DeleteTeamMember deletes a team membership.

(API) GetTeamMembers 

GetTeamMembers(teamId string, page, perPage int) ([]*model.TeamMember, *model.AppError)

GetTeamMembers returns the memberships of a specific team.

(API) GetTeamMember 

GetTeamMember(teamId, userId string) (*model.TeamMember, *model.AppError)

GetTeamMember returns a specific membership.

(API) UpdateTeamMemberRoles 

UpdateTeamMemberRoles(teamId, userId, newRoles string) (*model.TeamMember, *model.AppError)

UpdateTeamMemberRoles updates the role for a team membership.

(API) CreateChannel 

CreateChannel(channel *model.Channel) (*model.Channel, *model.AppError)

CreateChannel creates a channel.

(API) DeleteChannel 

DeleteChannel(channelId string) *model.AppError

DeleteChannel deletes a channel.

(API) GetPublicChannelsForTeam 

GetPublicChannelsForTeam(teamId string, page, perPage int) ([]*model.Channel, *model.AppError)

GetPublicChannelsForTeam gets a list of all channels.

(API) GetChannel 

GetChannel(channelId string) (*model.Channel, *model.AppError)

GetChannel gets a channel.

(API) GetChannelByName 

GetChannelByName(teamId, name string, includeDeleted bool) (*model.Channel, *model.AppError)

GetChannelByName gets a channel by its name, given a team id.

(API) GetChannelByNameForTeamName 

GetChannelByNameForTeamName(teamName, channelName string, includeDeleted bool) (*model.Channel, *model.AppError)

GetChannelByNameForTeamName gets a channel by its name, given a team name.

(API) GetChannelsForTeamForUser 

GetChannelsForTeamForUser(teamId, userId string, includeDeleted bool) ([]*model.Channel, *model.AppError)

GetChannelsForTeamForUser gets a list of channels for given user ID in given team ID.

Minimum server version: 5.6

(API) GetChannelStats 

GetChannelStats(channelId string) (*model.ChannelStats, *model.AppError)

GetChannelStats gets statistics for a channel.

Minimum server version: 5.6

(API) GetDirectChannel 

GetDirectChannel(userId1, userId2 string) (*model.Channel, *model.AppError)

GetDirectChannel gets a direct message channel. If the channel does not exist it will create it.

(API) GetGroupChannel 

GetGroupChannel(userIds []string) (*model.Channel, *model.AppError)

GetGroupChannel gets a group message channel. If the channel does not exist it will create it.

(API) UpdateChannel 

UpdateChannel(channel *model.Channel) (*model.Channel, *model.AppError)

UpdateChannel updates a channel.

(API) SearchChannels 

SearchChannels(teamId string, term string) ([]*model.Channel, *model.AppError)

SearchChannels returns the channels on a team matching the provided search term.

Minimum server version: 5.6

(API) SearchUsers 

SearchUsers(search *model.UserSearch) ([]*model.User, *model.AppError)

SearchUsers returns a list of users based on some search criteria.

Minimum server version: 5.6

(API) AddChannelMember 

AddChannelMember(channelId, userId string) (*model.ChannelMember, *model.AppError)

AddChannelMember creates a channel membership for a user.

(API) GetChannelMember 

GetChannelMember(channelId, userId string) (*model.ChannelMember, *model.AppError)

GetChannelMember gets a channel membership for a user.

(API) GetChannelMembers 

GetChannelMembers(channelId string, page, perPage int) (*model.ChannelMembers, *model.AppError)

GetChannelMembers gets a channel membership for all users.

Minimum server version: 5.6

(API) GetChannelMembersByIds 

GetChannelMembersByIds(channelId string, userIds []string) (*model.ChannelMembers, *model.AppError)

GetChannelMembersByIds gets a channel membership for a particular User

Minimum server version: 5.6

(API) UpdateChannelMemberRoles 

UpdateChannelMemberRoles(channelId, userId, newRoles string) (*model.ChannelMember, *model.AppError)

UpdateChannelMemberRoles updates a user's roles for a channel.

(API) UpdateChannelMemberNotifications 

UpdateChannelMemberNotifications(channelId, userId string, notifications map[string]string) (*model.ChannelMember, *model.AppError)

UpdateChannelMemberNotifications updates a user's notification properties for a channel.

(API) DeleteChannelMember 

DeleteChannelMember(channelId, userId string) *model.AppError

DeleteChannelMember deletes a channel membership for a user.

(API) CreatePost 

CreatePost(post *model.Post) (*model.Post, *model.AppError)

CreatePost creates a post.

(API) AddReaction 

AddReaction(reaction *model.Reaction) (*model.Reaction, *model.AppError)

AddReaction add a reaction to a post.

Minimum server version: 5.3

(API) RemoveReaction 

RemoveReaction(reaction *model.Reaction) *model.AppError

RemoveReaction remove a reaction from a post.

Minimum server version: 5.3

(API) GetReactions 

GetReactions(postId string) ([]*model.Reaction, *model.AppError)

GetReaction get the reactions of a post.

Minimum server version: 5.3

(API) SendEphemeralPost 

SendEphemeralPost(userId string, post *model.Post) *model.Post

SendEphemeralPost creates an ephemeral post.

(API) DeletePost 

DeletePost(postId string) *model.AppError

DeletePost deletes a post.

(API) GetPostThread 

GetPostThread(postId string) (*model.PostList, *model.AppError)

GetPostThread gets a post with all the other posts in the same thread.

Minimum server version: 5.6

(API) GetPost 

GetPost(postId string) (*model.Post, *model.AppError)

GetPost gets a post.

(API) GetPostsSince 

GetPostsSince(channelId string, time int64) (*model.PostList, *model.AppError)

GetPostsSince gets posts created after a specified time as Unix time in milliseconds.

Minimum server version: 5.6

(API) GetPostsAfter 

GetPostsAfter(channelId, postId string, page, perPage int) (*model.PostList, *model.AppError)

GetPostsAfter gets a page of posts that were posted after the post provided.

Minimum server version: 5.6

(API) GetPostsBefore 

GetPostsBefore(channelId, postId string, page, perPage int) (*model.PostList, *model.AppError)

GetPostsBefore gets a page of posts that were posted before the post provided.

Minimum server version: 5.6

(API) GetPostsForChannel 

GetPostsForChannel(channelId string, page, perPage int) (*model.PostList, *model.AppError)

GetPostsForChannel gets a list of posts for a channel.

Minimum server version: 5.6

(API) UpdatePost 

UpdatePost(post *model.Post) (*model.Post, *model.AppError)

UpdatePost updates a post.

(API) GetProfileImage 

GetProfileImage(userId string) ([]byte, *model.AppError)

GetProfileImage gets user's profile image.

Minimum server version: 5.6

(API) SetProfileImage 

SetProfileImage(userId string, data []byte) *model.AppError

SetProfileImage sets a user's profile image.

Minimum server version: 5.6

(API) GetEmojiList 

GetEmojiList(sortBy string, page, perPage int) ([]*model.Emoji, *model.AppError)

GetEmojiList returns a page of custom emoji on the system.

The sortBy parameter can be: "name".

Minimum server version: 5.6

(API) GetEmojiByName 

GetEmojiByName(name string) (*model.Emoji, *model.AppError)

GetEmojiByName gets an emoji by it's name.

Minimum server version: 5.6

(API) GetEmoji 

GetEmoji(emojiId string) (*model.Emoji, *model.AppError)

GetEmoji returns a custom emoji based on the emojiId string.

Minimum server version: 5.6

(API) CopyFileInfos 

CopyFileInfos(userId string, fileIds []string) ([]string, *model.AppError)

CopyFileInfos duplicates the FileInfo objects referenced by the given file ids, recording the given user id as the new creator and returning the new set of file ids.

The duplicate FileInfo objects are not initially linked to a post, but may now be passed to CreatePost. Use this API to duplicate a post and its file attachments without actually duplicating the uploaded files.

(API) GetFileInfo 

GetFileInfo(fileId string) (*model.FileInfo, *model.AppError)

GetFileInfo gets a File Info for a specific fileId

Minimum server version: 5.3

(API) GetFile 

GetFile(fileId string) ([]byte, *model.AppError)

GetFile gets content of a file by it's ID

Minimum Server version: 5.8

GetFileLink(fileId string) (string, *model.AppError)

GetFileLink gets the public link to a file by fileId.

Minimum server version: 5.6

(API) ReadFile 

ReadFile(path string) ([]byte, *model.AppError)

ReadFileAtPath reads the file from the backend for a specific path

Minimum server version: 5.3

(API) GetEmojiImage 

GetEmojiImage(emojiId string) ([]byte, string, *model.AppError)

GetEmojiImage returns the emoji image.

Minimum server version: 5.6

(API) UploadFile 

UploadFile(data []byte, channelId string, filename string) (*model.FileInfo, *model.AppError)

UploadFile will upload a file to a channel using a multipart request, to be later attached to a post.

Minimum server version: 5.6

(API) OpenInteractiveDialog 

OpenInteractiveDialog(dialog model.OpenDialogRequest) *model.AppError

OpenInteractiveDialog will open an interactive dialog on a user's client that generated the trigger ID. Used with interactive message buttons, menus and slash commands.

Minimum server version: 5.6

(API) GetPlugins 

GetPlugins() ([]*model.Manifest, *model.AppError)

GetPlugins will return a list of plugin manifests for currently active plugins.

Minimum server version: 5.6

(API) EnablePlugin 

EnablePlugin(id string) *model.AppError

EnablePlugin will enable an plugin installed.

Minimum server version: 5.6

(API) DisablePlugin 

DisablePlugin(id string) *model.AppError

DisablePlugin will disable an enabled plugin.

Minimum server version: 5.6

(API) RemovePlugin 

RemovePlugin(id string) *model.AppError

RemovePlugin will disable and delete a plugin.

Minimum server version: 5.6

(API) GetPluginStatus 

GetPluginStatus(id string) (*model.PluginStatus, *model.AppError)

GetPluginStatus will return the status of a plugin.

Minimum server version: 5.6

(API) KVSet 

KVSet(key string, value []byte) *model.AppError

KVSet will store a key-value pair, unique per plugin.

(API) KVSetWithExpiry 

KVSetWithExpiry(key string, value []byte, expireInSeconds int64) *model.AppError

KVSet will store a key-value pair, unique per plugin with an expiry time

Minimum server version: 5.6

(API) KVGet 

KVGet(key string) ([]byte, *model.AppError)

KVGet will retrieve a value based on the key. Returns nil for non-existent keys.

(API) KVDelete 

KVDelete(key string) *model.AppError

KVDelete will remove a key-value pair. Returns nil for non-existent keys.

(API) KVDeleteAll 

KVDeleteAll() *model.AppError

KVDeleteAll will remove all key-value pairs for a plugin.

Minimum server version: 5.6

(API) KVList 

KVList(page, perPage int) ([]string, *model.AppError)

KVList will list all keys for a plugin.

Minimum server version: 5.6

(API) PublishWebSocketEvent 

PublishWebSocketEvent(event string, payload map[string]interface{}, broadcast *model.WebsocketBroadcast) 

PublishWebSocketEvent sends an event to WebSocket connections. event is the type and will be prepended with "custom_<pluginid>_" payload is the data sent with the event. Interface values must be primitive Go types or mattermost-server/model types broadcast determines to which users to send the event

(API) HasPermissionTo 

HasPermissionTo(userId string, permission *model.Permission) bool

HasPermissionTo check if the user has the permission at system scope.

Minimum server version: 5.3

(API) HasPermissionToTeam 

HasPermissionToTeam(userId, teamId string, permission *model.Permission) bool

HasPermissionToTeam check if the user has the permission at team scope.

Minimum server version: 5.3

(API) HasPermissionToChannel 

HasPermissionToChannel(userId, channelId string, permission *model.Permission) bool

HasPermissionToChannel check if the user has the permission at channel scope.

Minimum server version: 5.3

(API) LogDebug 

LogDebug(msg string, keyValuePairs ...interface{}) 

LogDebug writes a log message to the Mattermost server log file. Appropriate context such as the plugin name will already be added as fields so plugins do not need to add that info. keyValuePairs should be primitive go types or other values that can be encoded by encoding/gob

(API) LogInfo 

LogInfo(msg string, keyValuePairs ...interface{}) 

LogInfo writes a log message to the Mattermost server log file. Appropriate context such as the plugin name will already be added as fields so plugins do not need to add that info. keyValuePairs should be primitive go types or other values that can be encoded by encoding/gob

(API) LogError 

LogError(msg string, keyValuePairs ...interface{}) 

LogError writes a log message to the Mattermost server log file. Appropriate context such as the plugin name will already be added as fields so plugins do not need to add that info. keyValuePairs should be primitive go types or other values that can be encoded by encoding/gob

(API) LogWarn 

LogWarn(msg string, keyValuePairs ...interface{}) 

LogWarn writes a log message to the Mattermost server log file. Appropriate context such as the plugin name will already be added as fields so plugins do not need to add that info. keyValuePairs should be primitive go types or other values that can be encoded by encoding/gob


Hooks

(Hooks) OnActivate 

OnActivate() error

OnActivate is invoked when the plugin is activated. If an error is returned, the plugin will be terminated. The plugin will not receive hooks until after OnActivate returns without error.

(Hooks) Implemented 

Implemented() ([]string, error)

Implemented returns a list of hooks that are implemented by the plugin. Plugins do not need to provide an implementation. Any given will be ignored.

(Hooks) OnDeactivate 

OnDeactivate() error

OnDeactivate is invoked when the plugin is deactivated. This is the plugin's last chance to use the API, and the plugin will be terminated shortly after this invocation. The plugin will stop receiving hooks just prior to this method being called.

(Hooks) OnConfigurationChange 

OnConfigurationChange() error

OnConfigurationChange is invoked when configuration changes may have been made. Any returned error is logged, but does not stop the plugin. You must be prepared to handle a configuration failure gracefully.

(Hooks) ServeHTTP 

ServeHTTP(c *plugin.Context, w http.ResponseWriter, r *http.Request) 

ServeHTTP allows the plugin to implement the http.Handler interface. Requests destined for the /plugins/{id} path will be routed to the plugin.

The Mattermost-User-Id header will be present if (and only if) the request is by an authenticated user.

(Hooks) ExecuteCommand 

ExecuteCommand(c *plugin.Context, args *model.CommandArgs) (*model.CommandResponse, *model.AppError)

ExecuteCommand executes a command that has been previously registered via the RegisterCommand API.

(Hooks) MessageWillBePosted 

MessageWillBePosted(c *plugin.Context, post *model.Post) (*model.Post, string)

MessageWillBePosted is invoked when a message is posted by a user before it is committed to the database. If you also want to act on edited posts, see MessageWillBeUpdated.

To reject a post, return an non-empty string describing why the post was rejected. To modify the post, return the replacement, non-nil *model.Post and an empty string. To allow the post without modification, return a nil *model.Post and an empty string.

If you don't need to modify or reject posts, use MessageHasBeenPosted instead.

Note that this method will be called for posts created by plugins, including the plugin that created the post.

(Hooks) MessageWillBeUpdated 

MessageWillBeUpdated(c *plugin.Context, newPost, oldPost *model.Post) (*model.Post, string)

MessageWillBeUpdated is invoked when a message is updated by a user before it is committed to the database. If you also want to act on new posts, see MessageWillBePosted. Return values should be the modified post or nil if rejected and an explanation for the user. On rejection, the post will be kept in its previous state.

If you don't need to modify or rejected updated posts, use MessageHasBeenUpdated instead.

Note that this method will be called for posts updated by plugins, including the plugin that updated the post.

(Hooks) MessageHasBeenPosted 

MessageHasBeenPosted(c *plugin.Context, post *model.Post) 

MessageHasBeenPosted is invoked after the message has been committed to the database. If you need to modify or reject the post, see MessageWillBePosted Note that this method will be called for posts created by plugins, including the plugin that created the post.

(Hooks) MessageHasBeenUpdated 

MessageHasBeenUpdated(c *plugin.Context, newPost, oldPost *model.Post) 

MessageHasBeenUpdated is invoked after a message is updated and has been updated in the database. If you need to modify or reject the post, see MessageWillBeUpdated Note that this method will be called for posts created by plugins, including the plugin that created the post.

(Hooks) ChannelHasBeenCreated 

ChannelHasBeenCreated(c *plugin.Context, channel *model.Channel) 

ChannelHasBeenCreated is invoked after the channel has been committed to the database.

(Hooks) UserHasJoinedChannel 

UserHasJoinedChannel(c *plugin.Context, channelMember *model.ChannelMember, actor *model.User) 

UserHasJoinedChannel is invoked after the membership has been committed to the database. If actor is not nil, the user was invited to the channel by the actor.

(Hooks) UserHasLeftChannel 

UserHasLeftChannel(c *plugin.Context, channelMember *model.ChannelMember, actor *model.User) 

UserHasLeftChannel is invoked after the membership has been removed from the database. If actor is not nil, the user was removed from the channel by the actor.

(Hooks) UserHasJoinedTeam 

UserHasJoinedTeam(c *plugin.Context, teamMember *model.TeamMember, actor *model.User) 

UserHasJoinedTeam is invoked after the membership has been committed to the database. If actor is not nil, the user was added to the team by the actor.

(Hooks) UserHasLeftTeam 

UserHasLeftTeam(c *plugin.Context, teamMember *model.TeamMember, actor *model.User) 

UserHasLeftTeam is invoked after the membership has been removed from the database. If actor is not nil, the user was removed from the team by the actor.

(Hooks) UserWillLogIn 

UserWillLogIn(c *plugin.Context, user *model.User) string

UserWillLogIn before the login of the user is returned. Returning a non empty string will reject the login event. If you don't need to reject the login event, see UserHasLoggedIn

(Hooks) UserHasLoggedIn 

UserHasLoggedIn(c *plugin.Context, user *model.User) 

UserHasLoggedIn is invoked after a user has logged in.

(Hooks) FileWillBeUploaded 

FileWillBeUploaded(c *plugin.Context, info *model.FileInfo, file io.Reader, output io.Writer) (*model.FileInfo, string)

FileWillBeUploaded is invoked when a file is uploaded, but before it is committed to backing store. Read from file to retrieve the body of the uploaded file.

To reject a file upload, return an non-empty string describing why the file was rejected. To modify the file, write to the output and/or return a non-nil *model.FileInfo, as well as an empty string. To allow the file without modification, do not write to the output and return a nil *model.FileInfo and an empty string.

Note that this method will be called for files uploaded by plugins, including the plugin that uploaded the post. FileInfo.Size will be automatically set properly if you modify the file.


Examples

(Example) HelloWorld 

This example demonstrates a plugin that handles HTTP requests which respond by greeting the world.

package main

import (
	"fmt"
	"net/http"

	"github.com/mattermost/mattermost-server/plugin"
)

type HelloWorldPlugin struct {
	plugin.MattermostPlugin
}

func (p *HelloWorldPlugin) ServeHTTP(c *plugin.Context, w http.ResponseWriter, r *http.Request) {
	fmt.Fprint(w, "Hello, world!")
}

// This example demonstrates a plugin that handles HTTP requests which respond by greeting the
// world.
func main() {
	plugin.ClientMain(&HelloWorldPlugin{})
}

(Example) HelpPlugin 

package main

import (
	"strings"
	"sync"

	"github.com/pkg/errors"

	"github.com/mattermost/mattermost-server/model"
	"github.com/mattermost/mattermost-server/plugin"
)

// configuration represents the configuration for this plugin as exposed via the Mattermost
// server configuration.
type configuration struct {
	TeamName	string
	ChannelName	string

	// channelId is resolved when the public configuration fields above change
	channelId	string
}

type HelpPlugin struct {
	plugin.MattermostPlugin

	// configurationLock synchronizes access to the configuration.
	configurationLock	sync.RWMutex

	// configuration is the active plugin configuration. Consult getConfiguration and
	// setConfiguration for usage.
	configuration	*configuration
}

// getConfiguration retrieves the active configuration under lock, making it safe to use
// concurrently. The active configuration may change underneath the client of this method, but
// the struct returned by this API call is considered immutable.
func (p *HelpPlugin) getConfiguration() *configuration {
	p.configurationLock.RLock()
	defer p.configurationLock.RUnlock()

	if p.configuration == nil {
		return &configuration{}
	}

	return p.configuration
}

// setConfiguration replaces the active configuration under lock.
//
// Do not call setConfiguration while holding the configurationLock, as sync.Mutex is not
// reentrant.
func (p *HelpPlugin) setConfiguration(configuration *configuration) {
	// Replace the active configuration under lock.
	p.configurationLock.Lock()
	defer p.configurationLock.Unlock()
	p.configuration = configuration
}

// OnConfigurationChange updates the active configuration for this plugin under lock.
func (p *HelpPlugin) OnConfigurationChange() error {
	var configuration = new(configuration)

	// Load the public configuration fields from the Mattermost server configuration.
	if err := p.API.LoadPluginConfiguration(configuration); err != nil {
		return errors.Wrap(err, "failed to load plugin configuration")
	}

	team, err := p.API.GetTeamByName(configuration.TeamName)
	if err != nil {
		return errors.Wrapf(err, "failed to find team %s", configuration.TeamName)
	}

	channel, err := p.API.GetChannelByName(configuration.ChannelName, team.Id, false)
	if err != nil {
		return errors.Wrapf(err, "failed to find channel %s", configuration.ChannelName)
	}

	configuration.channelId = channel.Id

	p.setConfiguration(configuration)

	return nil
}

func (p *HelpPlugin) MessageHasBeenPosted(c *plugin.Context, post *model.Post) {
	configuration := p.getConfiguration()

	// Ignore posts not in the configured channel
	if post.ChannelId != configuration.channelId {
		return
	}

	// Ignore posts this plugin made.
	if sentByPlugin, _ := post.Props["sent_by_plugin"].(bool); sentByPlugin {
		return
	}

	// Ignore posts without a plea for help.
	if !strings.Contains(post.Message, "help") {
		return
	}

	p.API.SendEphemeralPost(post.UserId, &model.Post{
		ChannelId:	configuration.channelId,
		Message:	"You asked for help? Checkout https://about.mattermost.com/help/",
		Props: map[string]interface{}{
			"sent_by_plugin": true,
		},
	})
}

func main() {
	plugin.ClientMain(&HelpPlugin{})
}