在 React App 中使用 Knex JS 获取失败
Failed to Fetch using Knex JS in in React App
我有一个带有复选框的组件,我使用 postgres 通过本地主机数据库跟踪它。当我选中复选框时,将在 table netowrkusers 中插入一行,其中 id 列中包含登录用户 id,连接列中已选中的用户 id。未选中时它会删除该行。它似乎间歇性地工作 - 但我不断收到 'failed to fetch' 错误,最终数据库无法正确跟踪选中和未选中的框。知道 Knex 的人可以看看代码中是否存在缺陷吗?这是我正在使用的 Knex.js 代码。
app.post("/cb", (req, res) => {
const { loginuser, userid, ischecked } = req.body;
if (ischecked) {
console.log("flag is true");
db.transaction(trx => {
trx
.insert({
id: loginuser,
connections: userid
})
.into("networkusers")
.returning("id", "connections")
.then(() => {
console.log("committing");
trx.commit();
})
.catch(error => {
console.log("error", error);
trx.rollback();
});
}).catch(err => res.status(400).json(err));
} else {
console.log("flag is false");
db.transaction(trx => {
db("networkusers")
.where("id", "=", loginuser)
.andWhere("connections", "=", userid)
.del()
.returning("id", "connections")
.then(() => {
console.log("committing");
console.log(loginuser,userid)
trx.commit();
})
.catch(error => {
console.log("error", error);
trx.rollback();
});
}).catch(err => res.status(400).json(err));
}
});
这里是具有复选框逻辑的组件:
import React, { useState } from "react";
const onUpdateCB = (ischecked, loginuser, userid, setisChecked,handleCheck) => {
console.log(ischecked, loginuser, userid);
fetch('http://localhost:3000/cb', {
method: 'post',
headers: {'Content-Type':'application/json'},
body:JSON.stringify({
loginuser,
userid,
ischecked: ischecked
})
}).then(setisChecked(ischecked));
return
};
const Card = props => {
const [isChecked, setisChecked] = useState(props.ischecked);
return (
<div
className="pointer bg-light-green dib br3 pa3 ma2 shadow-5"
onClick={() => props.handleClick(props.id)}
>
<div>
<h3>{props.name}</h3>
<p>{props.company}</p>
<p>{props.phone}</p>
<p>{props.email}</p>
<p>{props.city}</p>
</div>
<div>
My Network
<input
className="largeCheckbox"
type="checkbox"
checked={isChecked}
onChange={() =>
onUpdateCB(!isChecked, props.loginuser.id, props.id, setisChecked,props.handleCheck)
}
/>
</div>
</div>
);
};
export default Card;
NetworkArray 组件:
import React from "react";
import Card from "./Card";
const NetworkArray = ({
network,
networkusers,
handleChange,
handleClick,
loginuser
}) => {
console.log("in network array", networkusers);
const cardComponent = network.map((user, i) => {
const ischecked = networkusers.filter(n => {
var nw = n.id === loginuser.id && n.connections === network[i].id;
return nw;
});
console.log("is it checked", ischecked);
return (
<Card
key={network[i].id}
name={network[i].firstname + " " + network[i].lastname}
company={network[i].company}
phone={network[i].phone}
email={network[i].email}
city={network[i].city}
ischecked={ischecked.length}
handleChange={handleChange}
handleClick={handleClick}
id={network[i].id}
loginuser={loginuser}
/>
);
});
return <div>{cardComponent}</div>;
};
export default NetworkArray;
这看起来不太正确:
db.transaction(trx => {
db("networkusers")
.where("id", "=", loginuser)
通常你会这样做:
db.transaction(trx => {
trx("networkusers")
.where("id", "=", loginuser)
或:
db.transaction(trx => {
db("networkusers")
.where("id", "=", loginuser)
.transacting(trx)
我怀疑问题是您没有始终如一地使用事务对象。参见 overview。
您还应该在数据库操作成功后做出响应(而不仅仅是在失败时)。所以像:
db
.transaction(trx => {
// ...query...
})
.then(() => res.json({ message: 'Success.' }))
.catch(err => res.status(400).json(err));
我有一个带有复选框的组件,我使用 postgres 通过本地主机数据库跟踪它。当我选中复选框时,将在 table netowrkusers 中插入一行,其中 id 列中包含登录用户 id,连接列中已选中的用户 id。未选中时它会删除该行。它似乎间歇性地工作 - 但我不断收到 'failed to fetch' 错误,最终数据库无法正确跟踪选中和未选中的框。知道 Knex 的人可以看看代码中是否存在缺陷吗?这是我正在使用的 Knex.js 代码。
app.post("/cb", (req, res) => {
const { loginuser, userid, ischecked } = req.body;
if (ischecked) {
console.log("flag is true");
db.transaction(trx => {
trx
.insert({
id: loginuser,
connections: userid
})
.into("networkusers")
.returning("id", "connections")
.then(() => {
console.log("committing");
trx.commit();
})
.catch(error => {
console.log("error", error);
trx.rollback();
});
}).catch(err => res.status(400).json(err));
} else {
console.log("flag is false");
db.transaction(trx => {
db("networkusers")
.where("id", "=", loginuser)
.andWhere("connections", "=", userid)
.del()
.returning("id", "connections")
.then(() => {
console.log("committing");
console.log(loginuser,userid)
trx.commit();
})
.catch(error => {
console.log("error", error);
trx.rollback();
});
}).catch(err => res.status(400).json(err));
}
});
这里是具有复选框逻辑的组件:
import React, { useState } from "react";
const onUpdateCB = (ischecked, loginuser, userid, setisChecked,handleCheck) => {
console.log(ischecked, loginuser, userid);
fetch('http://localhost:3000/cb', {
method: 'post',
headers: {'Content-Type':'application/json'},
body:JSON.stringify({
loginuser,
userid,
ischecked: ischecked
})
}).then(setisChecked(ischecked));
return
};
const Card = props => {
const [isChecked, setisChecked] = useState(props.ischecked);
return (
<div
className="pointer bg-light-green dib br3 pa3 ma2 shadow-5"
onClick={() => props.handleClick(props.id)}
>
<div>
<h3>{props.name}</h3>
<p>{props.company}</p>
<p>{props.phone}</p>
<p>{props.email}</p>
<p>{props.city}</p>
</div>
<div>
My Network
<input
className="largeCheckbox"
type="checkbox"
checked={isChecked}
onChange={() =>
onUpdateCB(!isChecked, props.loginuser.id, props.id, setisChecked,props.handleCheck)
}
/>
</div>
</div>
);
};
export default Card;
NetworkArray 组件:
import React from "react";
import Card from "./Card";
const NetworkArray = ({
network,
networkusers,
handleChange,
handleClick,
loginuser
}) => {
console.log("in network array", networkusers);
const cardComponent = network.map((user, i) => {
const ischecked = networkusers.filter(n => {
var nw = n.id === loginuser.id && n.connections === network[i].id;
return nw;
});
console.log("is it checked", ischecked);
return (
<Card
key={network[i].id}
name={network[i].firstname + " " + network[i].lastname}
company={network[i].company}
phone={network[i].phone}
email={network[i].email}
city={network[i].city}
ischecked={ischecked.length}
handleChange={handleChange}
handleClick={handleClick}
id={network[i].id}
loginuser={loginuser}
/>
);
});
return <div>{cardComponent}</div>;
};
export default NetworkArray;
这看起来不太正确:
db.transaction(trx => {
db("networkusers")
.where("id", "=", loginuser)
通常你会这样做:
db.transaction(trx => {
trx("networkusers")
.where("id", "=", loginuser)
或:
db.transaction(trx => {
db("networkusers")
.where("id", "=", loginuser)
.transacting(trx)
我怀疑问题是您没有始终如一地使用事务对象。参见 overview。
您还应该在数据库操作成功后做出响应(而不仅仅是在失败时)。所以像:
db
.transaction(trx => {
// ...query...
})
.then(() => res.json({ message: 'Success.' }))
.catch(err => res.status(400).json(err));