Hi, I am looking for a way to modify the error messages that gets thrown from failed user registration in Strapi /api/auth/local endpoint. From where do I customize or modify these error messages? You can check the image for more information.
Hey,
You can overwrite strapi register and / or login endpoint.
Create a file src/extensions/users-permissions/strapi-server.js and change the error messages you want to :
const _ = require('lodash');
const {
validateCallbackBody,
validateRegisterBody,
} = require('../../../node_modules/@strapi/plugin-users-permissions/server/controllers/validation/auth');
const {
getService,
} = require('../../../node_modules/@strapi/plugin-users-permissions/server/utils');
const utils = require('@strapi/utils');
const {ApplicationError, ValidationError} = utils.errors;
module.exports = (plugin) => {
plugin.controllers.auth.callback = async (ctx) => {
const provider = ctx.params.provider || 'local';
const params = ctx.request.body;
const store = strapi.store({type: 'plugin', name: 'users-permissions'});
const grantSettings = await store.get({key: 'grant'});
const grantProvider = provider === 'local' ? 'email' : provider;
if (!_.get(grantSettings, [grantProvider, 'enabled'])) {
throw new ApplicationError('This provider is disabled');
}
if (provider === 'local') {
await validateCallbackBody(params);
const {identifier} = params;
// Check if the user exists.
const user = await strapi.query('plugin::users-permissions.user').findOne({
where: {
provider,
$or: [{email: identifier.toLowerCase()}, {username: identifier}],
},
});
if (!user) {
throw new ValidationError('Invalid identifier or password replaced by custom error');
}
if (!user.password) {
throw new ValidationError('Invalid identifier or password replaced by custom error');
}
const validPassword = await getService('user').validatePassword(
params.password,
user.password
);
if (!validPassword) {
throw new ValidationError('Invalid identifier or password replaced by custom error');
}
const advancedSettings = await store.get({key: 'advanced'});
const requiresConfirmation = _.get(advancedSettings, 'email_confirmation');
if (requiresConfirmation && user.confirmed !== true) {
throw new ApplicationError('Your account email is not confirmed');
}
if (user.blocked === true) {
throw new ApplicationError('Your account has been blocked by an administrator');
}
return ctx.send({
jwt: getService('jwt').issue({id: user.id}),
user: await sanitizeUser(user, ctx),
});
}
// Connect the user with the third-party provider.
try {
const user = await getService('providers').connect(provider, ctx.query);
if (user.blocked) {
throw new ForbiddenError('Your account has been blocked by an administrator');
}
return ctx.send({
jwt: getService('jwt').issue({id: user.id}),
user: await sanitizeUser(user, ctx),
});
} catch (error) {
throw new ApplicationError(error.message);
}
}
plugin.controllers.auth.register = async (ctx) => {
// This code is the default code find in node_modules/@strapi/plugin-users-permissions/server/controllers/auth.js
const pluginStore = await strapi.store({type: 'plugin', name: 'users-permissions'});
const settings = await pluginStore.get({key: 'advanced'});
if (!settings.allow_register) {
throw new ApplicationError('Register action is currently disabled');
}
const {register} = strapi.config.get('plugin.users-permissions');
const alwaysAllowedKeys = ['username', 'password', 'email'];
const userModel = strapi.contentTypes['plugin::users-permissions.user'];
const {attributes} = userModel;
const nonWritable = getNonWritableAttributes(userModel);
const allowedKeys = compact(
concat(
alwaysAllowedKeys,
isArray(register?.allowedFields)
? // Note that we do not filter allowedFields in case a user explicitly chooses to allow a private or otherwise omitted field on registration
register.allowedFields // if null or undefined, compact will remove it
: // to prevent breaking changes, if allowedFields is not set in config, we only remove private and known dangerous user schema fields
// TODO V5: allowedFields defaults to [] when undefined and remove this case
Object.keys(attributes).filter(
(key) =>
!nonWritable.includes(key) &&
!attributes[key].private &&
![
// many of these are included in nonWritable, but we'll list them again to be safe and since we're removing this code in v5 anyway
// Strapi user schema fields
'confirmed',
'blocked',
'confirmationToken',
'resetPasswordToken',
'provider',
'id',
'role',
// other Strapi fields that might be added
'createdAt',
'updatedAt',
'createdBy',
'updatedBy',
'publishedAt', // d&p
'strapi_reviewWorkflows_stage', // review workflows
].includes(key)
)
)
);
const params = {
..._.pick(ctx.request.body, allowedKeys),
provider: 'local',
};
await validateRegisterBody(params);
const role = await strapi
.query('plugin::users-permissions.role')
.findOne({where: {type: settings.default_role}});
if (!role) {
throw new ApplicationError('Impossible to find the default role');
}
const {email, username, provider} = params;
const identifierFilter = {
$or: [
{email: email.toLowerCase()},
{username: email.toLowerCase()},
{username},
{email: username},
],
};
const conflictingUserCount = await strapi.query('plugin::users-permissions.user').count({
where: {...identifierFilter, provider},
});
if (conflictingUserCount > 0) {
throw new ApplicationError('Email or Username are already taken');
}
if (settings.unique_email) {
const conflictingUserCount = await strapi.query('plugin::users-permissions.user').count({
where: {...identifierFilter},
});
if (conflictingUserCount > 0) {
throw new ApplicationError('Email or Username are already taken');
}
}
const newUser = {
...params,
role: role.id,
email: email.toLowerCase(),
username,
confirmed: !settings.email_confirmation,
};
const user = await getService('user').add(newUser);
const sanitizedUser = await sanitizeUser(user, ctx);
if (settings.email_confirmation) {
try {
await getService('user').sendConfirmationEmail(sanitizedUser);
} catch (err) {
throw new ApplicationError(err.message);
}
return ctx.send({user: sanitizedUser});
}
const jwt = getService('jwt').issue(_.pick(user, ['id']));
return ctx.send({
jwt,
user: sanitizedUser,
});
}
return plugin;
}
Hope it helps you 
