我在使用帆时遇到了多重问题,因为我无法理解水线承诺及其逻辑。我应该如何处理水线和蓝鸟的承诺和回调?
我试过两个内置蓝鸟承诺,甚至还有一个async.waterfall
实现,并不能成功。
简而言之,我正在为执行数据库查询的API编写代码,并且通过试图使用回调函数,它从不响应。
这是我尝试过纯的承诺:
changeFormation: function (request,response) {
console.log("changeFormation");
var lineupId = request.params.id;
var newFormation = request.param('formation');
var newLineUp = request.param('lineup');
console.log("Receiving" + newFormation);
if (["5-4-1", "5-3-2", "4-5-1", "4-4-2", "4-3-3", "3-5-2", "3-4-3"].indexOf(newFormation) === -1) {
console.log("No válida");
return response.send(409, "La táctica elegida no es válida");
}
LineUp.findOne({id: lineupId}).
then(function (foundLineUp) {
console.log(foundLineUp);
if (!foundLineUp)
return response.send(404);
if (! foundLineUp.formation) {
foundLineUp.formation = newFormation;
LineUp.update({id: foundLineUp.id}, foundLineUp).exec(function (err, saved) {
if (err)
return response.send(500, JSON.stringify(err));
return response.send(202, JSON.stringify(saved));
});
}
// If a formation was previously set
else if (Array.isArray(newLineUp) && newLineUp.length > 0) {
newLineUp.formation = newFormation;
LineUp.update({id: newLineUp.id}, newLineUp).exec(function (err,saved) {
if (err)
return response.send(500,JSON.stringify(err));
return response.stringify(202, JSON.stringify(saved));
});
}
console.log("Never reached");
}).
catch(function (err) {
console.log(err);
response.send(500,JSON.stringify(err));
});
},
在这上面,我可以在控制台"Never reached"
看到。为什么!?
而这正是我试图使用异步模块:
addPlayer: function (request,response) {
// console.log("Add player");
var lineupId = request.params.id;
var receivedPlayer = request.param('player');
var playerId = receivedPlayer.id;
var bench = receivedPlayer.bench;
var place = receivedPlayer.place;
var e, r;
async.waterfall([
function (cb) {
LineUp.findOne().where({id: lineupId}).exec(function (err, foundLineUp) {
cb(err,foundLineUp);
});},
function (lineup,cb) {
Player.findOne().where({id: playerId}).exec(function (err,foundPlayer) {
cb(err,lineup, foundPlayer);
});},
function (lineup, player, cb) {
if (!player) {
console.log("Jugador no existe");
cb(null, {status: 409, msg: "El jugador " + playerId + " no existe"});
}
if (!lineup.formation) {
console.log("No hay táctica")
cb(null, {status: 409, msg: "No se ha elegido una táctica para esta alineación"});
}
if (lineup.squadIsComplete()) {
console.log("Ya hay 15");
cb(null, {status: 409, msg: "La plantilla ya contiene el máximo de 15 jugadores"});
}
if (lineup.playerWasAdded(player.id)) {
console.log("Jugador ya en alineación")
cb(null, {status: 409, msg: "El jugador ya ha sido agregado a la alineación"});
}
if (lineup.fieldIsComplete() && !bench) {
console.log("Ya hay 11 en el campo");
cb(null, {status: 409, msg: "Ya se han agregado los 11 jugadores de campo"});
}
player.bench = bench;
player.place = place;
lineup.players.push(player);
console.log("MaxForeign " + lineup.reachesMaxForeignPlayers());
console.log("BudgetLimit " + lineup.reachesBudgetLimit());
console.log("SameTeam " + lineup.reachesMaxSameTeamLimit());
console.log("reachesMaxSameFavoriteTeamLimit " + lineup.reachesMaxSameFavoriteTeamLimit());
// If any of rule restrictions evaluates to true ...
// Using lodash _.some with out second argument which defaults to _.identity
/* if (_.some([ lineup.reachesMaxForeignPlayers(),
lineup.reachesBudgetLimit(),
lineup.reachesMaxSameTeamLimit(),
lineup.reachesMaxSameFavoriteTeamLimit()])) {
return response.send(409, "La inclusión de este jugador no satisface las reglas del juego");
}*/
LineUp.update({id: playerId}, lineup).exec(function (err, saved) {
cb(err, {status: 202, msg: JSON.stringify(saved)});
});
}
],
function (err, result) {
console.log("About to respond");
if (err)
respond.send(500);
else
response.send(result.status, result.msg);
});
console.log("Never reached");
},
这给不超时,但它并不奇怪,当它应该更新文档。它的日志记录"never reached"
然后"about to respond"
但这是正常的,我猜。
到目前为止,我该如何处理这一切?
为什么你会期待'console.log(“永远不会到达”);'永远不会到达?没有达到的唯一情况就是发送404。 – Bergi
嗯,这两个代码片段似乎完全不相关,并使用不同的方法。请只询问每个问题的单个问题(尽管您可能包含多种不同的方法来解决问题) – Bergi