对于项目中的网络请求一般会包含以下几个部分：
- 统一处理请求错误（可以在指定节点增加错误日志收集等）
- cookie封装
- 默认参数设置
统一处理请求
以上问题都是高频且大致相同的动作，所以比较合适做一层统一封装，根据具体业务不同封装的点肯定有很大不同，这里只是总结了几个比较常见的需求。
先看具体调用代码：
Map result = await request('/api/user/login',
data: {'account': account, 'password': password});
if (result != null) {
Application.router.navigateTo(context, '/home',replace:true);
}
网络请求request中定义几个逻辑：服务端异常或者逻辑错误的时候直接在request中进行处理，并且返回null，所以使用的时候直接判断结果是否为null来判断请求是否正确，如果正确走后续处理逻辑，否则视具体业务场景决定是否要做更多额外的处理（默认是会把服务器返回的错误数据toast出来）。
cookie封装
dio本身已经提供了比较好用的包dio_cookie_manager(需要额外引入)，但是该包的CookieManager有点小问题，就是如果服务端的cookie包含了一些特殊字符，如:[];()@,?=等，会导致解析报错，并抛出以下异常：
formatexception: invalid character in cookie name, code unit: '58' (at character 4)
这里主要是因为默认的cookie会检测具体的cookie值，包含上述说的字符的时候会抛异常，但是因为这个去更改后端的cookie的机制肯定不现实，只能前端处理了。这里直接贴代码了：
import 'dart:async';
import 'dart:io';
import 'package:dio_cookie_manager/dio_cookie_manager.dart';
import 'package:cookie_jar/cookie_jar.dart';
import 'package:dio/dio.dart';
class PrivateCookieManager extends CookieManager {
PrivateCookieManager(CookieJar cookieJar) : super(cookieJar);
@override
Future onResponse(Response response) async => _saveCookies(response);
@override
Future onError(DioError err) async => _saveCookies(err.response);
_saveCookies(Response response) {
print("_saveCookies response = $response");
if (response != null && response.headers != null) {
List<String> cookies = response.headers[HttpHeaders.setCookieHeader];
if (cookies != null) {
cookieJar.saveFromResponse(
response.request.uri,
cookies.map((str) => _Cookie.fromSetCookieValue(str)).toList(),
);
}
}
}
}
class _Cookie implements Cookie {
String name;
String value;
DateTime expires;
int maxAge;
String domain;
String path;
bool httpOnly = false;
bool secure = false;
_Cookie([this.name, this.value]) {
// Default value of httponly is true.
httpOnly = true;
_validate();
}
_Cookie.fromSetCookieValue(String value) {
// Parse the 'set-cookie' header value.
_parseSetCookieValue(value);
}
// Parse a 'set-cookie' header value according to the rules in RFC 6265.
void _parseSetCookieValue(String s) {
int index = 0;
bool done() => index == s.length;
String parseName() {
int start = index;
while (!done()) {
if (s[index] == "=") break;
index++;
}
return s.substring(start, index).trim();
}
String parseValue() {
int start = index;
while (!done()) {
if (s[index] == ";") break;
index++;
}
return s.substring(start, index).trim();
}
void expect(String expected) {
if (done()) throw new HttpException("Failed to parse header value [$s]");
if (s[index] != expected) {
throw new HttpException("Failed to parse header value [$s]");
}
index++;
}
void parseAttributes() {
String parseAttributeName() {
int start = index;
while (!done()) {
if (s[index] == "=" || s[index] == ";") break;
index++;
}
return s.substring(start, index).trim().toLowerCase();
}
String parseAttributeValue() {
int start = index;
while (!done()) {
if (s[index] == ";") break;
index++;
}
return s.substring(start, index).trim().toLowerCase();
}
while (!done()) {
String name = parseAttributeName();
String value = "";
if (!done() && s[index] == "=") {
index++; // Skip the = character.
value = parseAttributeValue();
}
if (name == "expires") {
expires = _parseCookieDate(value);
} else if (name == "max-age") {
maxAge = int.parse(value);
} else if (name == "domain") {
domain = value;
} else if (name == "path") {
path = value;
} else if (name == "httponly") {
httpOnly = true;
} else if (name == "secure") {
secure = true;
}
if (!done()) index++; // Skip the ; character
}
}
name = parseName();
if (done() || name.length == 0) {
throw new HttpException("Failed to parse header value [$s]");
}
index++; // Skip the = character.
value = parseValue();
_validate();
if (done()) return;
index++; // Skip the ; character.
parseAttributes();
}
String toString() {
StringBuffer sb = new StringBuffer();
sb..write(name)..write("=")..write(value);
if (expires != null) {
sb..write("; Expires=")..write(HttpDate.format(expires));
}
if (maxAge != null) {
sb..write("; Max-Age=")..write(maxAge);
}
if (domain != null) {
sb..write("; Domain=")..write(domain);
}
if (path != null) {
sb..write("; Path=")..write(path);
}
if (secure) sb.write("; Secure");
if (httpOnly) sb.write("; HttpOnly");
return sb.toString();
}
void _validate() {
const separators = const [
"(",
")",
"<",
">",
"@",
",",
";",
// ":",
"\\",
'"',
"/",
// "[",
// "]",
"?",
"=",
"{",
"}"
];
for (int i = 0; i < name.length; i++) {
int codeUnit = name.codeUnits[i];
if (codeUnit <= 32 ||
codeUnit >= 127 ||
separators.indexOf(name[i]) >= 0) {
throw new FormatException(
"Invalid character in cookie name, code unit: '$codeUnit'",
name,
i);
}
}
// Per RFC 6265, consider surrounding "" as part of the value, but otherwise
// double quotes are not allowed.
int start = 0;
int end = value.length;
if (2 <= value.length &&
value.codeUnits[start] == 0x22 &&
value.codeUnits[end - 1] == 0x22) {
start++;
end--;
}
for (int i = start; i < end; i++) {
int codeUnit = value.codeUnits[i];
if (!(codeUnit == 0x21 ||
(codeUnit >= 0x23 && codeUnit <= 0x2B) ||
(codeUnit >= 0x2D && codeUnit <= 0x3A) ||
(codeUnit >= 0x3C && codeUnit <= 0x5B) ||
(codeUnit >= 0x5D && codeUnit <= 0x7E))) {
throw new FormatException(
"Invalid character in cookie value, code unit: '$codeUnit'",
value,
i);
}
}
}
// Parse a cookie date string.
static DateTime _parseCookieDate(String date) {
const List monthsLowerCase = const [
"jan",
"feb",
"mar",
"apr",
"may",
"jun",
"jul",
"aug",
"sep",
"oct",
"nov",
"dec"
];
int position = 0;
void error() {
throw new HttpException("Invalid cookie date $date");
}
bool isEnd() => position == date.length;
bool isDelimiter(String s) {
int char = s.codeUnitAt(0);
if (char == 0x09) return true;
if (char >= 0x20 && char <= 0x2F) return true;
if (char >= 0x3B && char <= 0x40) return true;
if (char >= 0x5B && char <= 0x60) return true;
if (char >= 0x7B && char <= 0x7E) return true;
return false;
}
bool isNonDelimiter(String s) {
int char = s.codeUnitAt(0);
if (char >= 0x00 && char <= 0x08) return true;
if (char >= 0x0A && char <= 0x1F) return true;
if (char >= 0x30 && char <= 0x39) return true; // Digit
if (char == 0x3A) return true; // ':'
if (char >= 0x41 && char <= 0x5A) return true; // Alpha
if (char >= 0x61 && char <= 0x7A) return true; // Alpha
if (char >= 0x7F && char <= 0xFF) return true; // Alpha
return false;
}
bool isDigit(String s) {
int char = s.codeUnitAt(0);
if (char > 0x2F && char < 0x3A) return true;
return false;
}
int getMonth(String month) {
if (month.length < 3) return -1;
return monthsLowerCase.indexOf(month.substring(0, 3));
}
int toInt(String s) {
int index = 0;
for (; index < s.length && isDigit(s[index]); index++);
return int.parse(s.substring(0, index));
}
var tokens = [];
while (!isEnd()) {
while (!isEnd() && isDelimiter(date[position])) position++;
int start = position;
while (!isEnd() && isNonDelimiter(date[position])) position++;
tokens.add(date.substring(start, position).toLowerCase());
while (!isEnd() && isDelimiter(date[position])) position++;
}
String timeStr;
String dayOfMonthStr;
String monthStr;
String yearStr;
for (var token in tokens) {
if (token.length < 1) continue;
if (timeStr == null &&
token.length >= 5 &&
isDigit(token[0]) &&
(token[1] == ":" || (isDigit(token[1]) && token[2] == ":"))) {
timeStr = token;
} else if (dayOfMonthStr == null && isDigit(token[0])) {
dayOfMonthStr = token;
} else if (monthStr == null && getMonth(token) >= 0) {
monthStr = token;
} else if (yearStr == null &&
token.length >= 2 &&
isDigit(token[0]) &&
isDigit(token[1])) {
yearStr = token;
}
}
if (timeStr == null ||
dayOfMonthStr == null ||
monthStr == null ||
yearStr == null) {
error();
}
int year = toInt(yearStr);
if (year >= 70 && year <= 99)
year += 1900;
else if (year >= 0 && year <= 69) year += 2000;
if (year < 1601) error();
int dayOfMonth = toInt(dayOfMonthStr);
if (dayOfMonth < 1 || dayOfMonth > 31) error();
int month = getMonth(monthStr) + 1;
var timeList = timeStr.split(":");
if (timeList.length != 3) error();
int hour = toInt(timeList[0]);
int minute = toInt(timeList[1]);
int second = toInt(timeList[2]);
if (hour > 23) error();
if (minute > 59) error();
if (second > 59) error();
return new DateTime.utc(year, month, dayOfMonth, hour, minute, second, 0);
}
}
然后在使用的时候将自带的CookieManage替换为刚才的PrivateCookieManage即可：
CookieJar cookieJar = CookieJar();
dio.interceptors.add(PrivateCookieManager(cookieJar));
本文为原创文章，转载请保留原出处。原文地址：https:/eatong.cn/blog/18
网友评论