不管是微信支付还是支付宝支付， 3个最棘手的问题是：

1，如何生成签名

2，支付请求如何提交

3, 如何验证签名

下面就围绕这二个问题来讲。

我使用的是XE3.

先看微信支付：

1，微信支付的签名生成

uses IdHashMessageDigest, NatvieXml; //我使用的是NativeXml4.07

function TMicroPayParamBuilder.GetSign: string;

var

Digest: TIdHashMessageDigest5;

utf8: UTF8String;

begin

utf8 := '';

Assert(FAppId <> '', '公众账号ID 不能为空！');

utf8 := utf8 + 'appid=' + FAppId;

if FAttach <> '' then

utf8 := utf8 + '&attach=' + FAttach;

Assert(FAuthCode <> '', '授权码 不能为空！');

utf8 := utf8 + '&auth_code=' + FAuthCode;

Assert(FBody <> '', '商品描述 不能为空！');

utf8 := utf8 + '&body=' + FBody;

if FDetail <> '' then

utf8 := utf8 + '&detail=' + BuildDetail();

Assert(FMchId <> '', '商户号 不能为空！');

utf8 := utf8 + '&mch_id=' + FMchId;

utf8 := utf8 + '&nonce_str=' + FNonceStr;

Assert(FOutTradeNo <> '', '商户订单号 不能为空！');

utf8 := utf8 + '&out_trade_no=' + FOutTradeNo;

Assert(FSpbillCreateIp <> '', '终端IP 不能为空！');

utf8 := utf8 + '&spbill_create_ip=' + FSpbillCreateIp;

Assert(FTotalFee > 0, '订单金额 必须大于0！');

utf8 := utf8 + '&total_fee=' + IntToStr(FTotalFee);

Assert(Fkey <> '', '密钥 不能为空！');

utf8 := utf8 + '&key=' + Fkey;

//计算签名

try

Digest:= TIdHashMessageDigest5.Create;

Result := Digest.HashBytesAsHex(BytesOf(utf8));

finally

Digest.Free;

end;

end;

//生成Http Post请求的数据

function TMicroPayParamBuilder.BuildParam: string;

var

xml : TNativeXml;

Node: TXmlNode;

begin

xml := TNativeXml.CreateEx(nil, False, False, True, 'xml');

try

Node:= xml.NodeNewTextType('appid', FAppId , xeElement);

xml.Root.NodeAdd(Node);

Node:= xml.NodeNewTextType('mch_id', FMchId , xeElement);

xml.Root.NodeAdd(Node);

Node:= xml.NodeNewTextType('nonce_str', FNonceStr , xeElement);

xml.Root.NodeAdd(Node);

Node:= xml.NodeNewTextType('sign', Sign , xeElement);

xml.Root.NodeAdd(Node);

Node:= xml.NodeNewTextType('body', FBody , xeElement);

xml.Root.NodeAdd(Node);

Node:= xml.NodeNewTextType('out_trade_no', FOutTradeNo , xeElement);

xml.Root.NodeAdd(Node);

Node:= xml.NodeNewIntType('total_fee', FTotalFee , xeElement);

xml.Root.NodeAdd(Node);

Node:= xml.NodeNewTextType('spbill_create_ip', FSpbillCreateIp , xeElement);

xml.Root.NodeAdd(Node);

Node:= xml.NodeNewTextType('auth_code', FAuthCode , xeElement);

xml.Root.NodeAdd(Node);

if FAttach <> '' then

begin

Node:= xml.NodeNewTextType('attach', FAttach , xeElement);

xml.Root.NodeAdd(Node);

end;

if FDetail <> '' then

begin

Node:= xml.NodeNewTextType('detail', BuildDetail() , xeElement);

xml.Root.NodeAdd(Node);

end;

Result := xml.WriteToString;

finally

xml.Free;

end;

end;

2, 微信支付请求如何提交

class function TTencentSSLHttpPost.Post(URL: string;

Builder: TBaseParamBuilder): string;

var

ssl:TIdSSLIOHandlerSocketOpenSSL;

http: TIdHttp;

inStrm, outStrm: TStringStream;

begin

http:= TIdHttp.Create(nil);

ssl:=TIdSSLIOHandlerSocketOpenSSL.Create(nil);

ssl.SSLOptions.Method := sslvSSLv23;

http.IOHandler := ssl;

inStrm:= TStringStream.Create(Builder.BuildParam, TEncoding.UTF8);

outStrm:= TStringStream.Create('', TEncoding.UTF8);

try

try

http.Post(URL, inStrm, outStrm);

Result := outStrm.DataString;

except

Result := '';

end;

finally

ssl.Free;

http.Free;

outStrm.Free;

inStrm.Free;

end;

end;

const URL_MicroPay = 'https://api.mch.weixin.qq.com/pay/micropay';

class function TMicroPayHttpUtils.PostRequest( Builder: TMicroPayParamBuilder): string;

begin Result := TTencentSSLHttpPost.Post(URL_MicroPay, Builder);

end;

微信如何验证签名：

TStringsHelper = class helper for TStrings

function Join(const Splitter: string): string;

end;

{ TMyStrings}

function TStringsHelper.Join(const Splitter: string): string;

var

I : Integer;

begin

Result := '';

for I := 0 to Self.Count - 1 do

Result := Result + Splitter + Self.Names[I] + '=' + Self.ValueFromIndex[I];

if Result <> '' then System.Delete(result, 1, Length(Splitter));

end;

function MyStringListSort(List: TStringList; Index1, Index2: Integer): Integer;

begin

Result := CompareStr(List.Names[Index1], List.Names[Index2]);

end;

function VerifyResponseSign(xml: TNativeXml; Key: string): Boolean; overload;

var

sign: string;

I : Integer;

List : TStringList;

utf8: UTF8String;

Digest: TIdHashMessageDigest5;

begin

Result := False;

if xml.Root.FindNode('sign') = nil then Exit;

sign := xml.Root.FindNode('sign').ValueUnicode;

List := TStringList.Create;

try

for I := 0 to xml.Root.NodeCount - 1 do

begin

if (xml.Root.Nodes[I].NameUnicode <> 'sign') and (xml.Root.Nodes[I].NameUnicode <> 'WhiteSpace')

and (xml.Root.Nodes[I].ValueUnicode <> '') then

List.Add(xml.Root.Nodes[I].NameUnicode + '=' + xml.Root.Nodes[I].ValueUnicode);

end;

List.CustomSort(MyStringListSort);

utf8 := List.Join('&') + '&key=' + key;

try

Digest:= TIdHashMessageDigest5.Create;

Result := SameText(Digest.HashBytesAsHex(BytesOf(utf8)), sign);

finally

Digest.Free;

end;

finally

List.Free;

end;

end;

function VerifyResponseSign(xml: TNativeXml): Boolean; overload;

begin

Result := VerifyResponseSign(xml, GetKey());

end;

function VerifyResponseSign(Response: string; Key: string): Boolean; overload;

var

xml: TNativeXml;

begin

Result := False;

xml := TNativeXml.Create(nil);

try

try

xml.ReadFromString(Response);

except

Exit;

end;

Result := VerifyResponseSign(xml, Key);

finally

xml.Free;

end;

end;

那么如何发送一个刷卡支付请求呢？

procedure TForm4.btn4Click(Sender: TObject);

var

Param: TMicroPayParamBuilder;

Response: string;

begin

Param:= TMicroPayParamBuilder.Create;

try

if edBody.Text <> '' then

Param.Body := edBody.Text;

Param.OutTradeNo:= edTradeNo.Text;

Param.SpbillCreateIp:=idpwtch1.LocalIP;

param.AuthCode:= edAuthCode.Text;

Param.Attach := edAttach.Text;

Param.TotalFee := 10;

param.AppId := edAppId.Text;

Param.MchId := edMch_id.Text;

Param.Key := edKey.Text;

mmo1.Lines.Append(Param.BuildParam);

mmo1.Lines.Append('-------------------------------------------');

Response := TMicroPayHttpUtils.PostRequest(Param);

if Response = '' then

begin

ShowMessage('请求出错！ 可能是网络不通！');

Exit;

end;

mmo1.Lines.Append(Response);

if not VerifyResponseSign(Response, GetKey()) then

showmessage('签名验证不通过！');

finally

Param.Free;

end;

end;