Google的搜索API的Delphi封装

{ Google搜索API
参考资料：
http://code.google.com/intl/zh-CN/apis/ajaxsearch/documentation/reference.html#_class_GSearch
作者：不得闲 2010-4-1
}
unit DxGoogleSearchApi;

interface
uses Classes,SysUtils,msxml,uLkJSON,Variants;

type
// 搜索类型 Web搜索 本地搜索 视频搜索 博客 新闻 书籍 图片 专利搜索
TDxSearchType = (Sh_Web,Sh_Local,Sh_Video,Sh_Blog,Sh_News,Sh_Book,Sh_Image,Sh_patent);

// 搜索返回的结果
TDxSearchRecord = class
private
RetList: TStringList;
function GetFieldCount: Integer;
function GetFields(index: Integer): string ;
function GetValues(index: Integer): string ;
public
constructor Create;
procedure FromJsonObj(JsonObj: TlkJSONobject);
destructor Destroy; override ;
property FieldCount: Integer read GetFieldCount;
property Fields[index: Integer]: string read GetFields;
property Values[index: Integer]: string read GetValues;
function FieldByName(FieldName: string ): string ;
end ;

TDxSearchRecords = class
private
List: TList;
FSearchType: TDxSearchType;
function GetCount: Integer;
function GetRecords(index: Integer): TDxSearchRecord;
public
procedure Clear;
constructor Create;
property SearchType: TDxSearchType read FSearchType;
destructor Destroy; override ;
property Count: Integer read GetCount;
property Records[index: Integer]: TDxSearchRecord read GetRecords;
end ;

// 搜索API
TDxGoogleSearch = class
private
FSearchType: TDxSearchType;
FBigSearchSize: Boolean;
FSearchStart: Integer;
FVersion: string ;
HttpReq: IXMLHttpRequest;
FRecords: TDxSearchRecords;
Pages: array of Integer;
FCurSearchInfo: string ;
ClearOld: Boolean;
FCurPageIndex: Integer;
function GetPageCount: Integer;
public
constructor Create;
destructor Destroy; override ;
procedure Search(SearchInfo: string );
property CurPageIndex: Integer read FCurPageIndex;
function NextSearch: Boolean; // 搜索下一个页
property PageCount: Integer read GetPageCount;
property Records: TDxSearchRecords read FRecords;
property BigSearchSize: Boolean read FBigSearchSize write FBigSearchSize default true; // rsz参数
property SearchStart: Integer read FSearchStart write FSearchStart default 0 ; // 搜索开始的位置，start参数
property Version: string read FVersion write FVersion;
property SearchType: TDxSearchType read FSearchType write FSearchType default Sh_Web; // 搜索类型
end ;
implementation

type
TBytes = array of Byte;

function BytesOf( const Val: AnsiString): TBytes;
var
Len: Integer;
begin
Len : = Length(Val);
SetLength(Result, Len);
Move(Val[ 1 ], Result[ 0 ], Len);
end ;

function ToUTF8Encode(str: string ): string ;
var
b: Byte;
begin
for b in BytesOf(UTF8Encode(str)) do
Result : = Format( ' %s%s%.2x ' , [Result, ' % ' , b]);
end ;


{ TDxGoogleSearch }

constructor TDxGoogleSearch.Create;
begin
HttpReq : = CoXMLHTTPRequest.Create;
ClearOld : = True;
FRecords : = TDxSearchRecords.Create;
FVersion : = ' 1.0 ' ;
FSearchType : = Sh_Web;
FBigSearchSize : = True;
FSearchStart : = 0 ;
end ;

destructor TDxGoogleSearch.Destroy;
begin
HttpReq : = nil ;
SetLength(Pages, 0 );
FRecords.Free;
inherited ;
end ;

function TDxGoogleSearch.GetPageCount: Integer;
begin
Result : = High(Pages) + 1 ;
end ;

function TDxGoogleSearch.NextSearch: Boolean;
var
i: Integer;
begin
Result : = False;
for i : = 0 to High(Pages) do
begin
if Pages[i] = FSearchStart then
begin
if i + 1 <= High(Pages) then
begin
FSearchStart : = Pages[i + 1 ];
Result : = True;
end ;
Break;
end ;
end ;
if Result then
Search(FCurSearchInfo);
end ;

procedure TDxGoogleSearch.Search(SearchInfo: string );
const
BaseUrl = ' http://ajax.googleapis.com/ajax/services/search/ ' ;
var
Url: string ;
Json: TlkJsonObject;
ChildJson,tmpJson: TlkJSONbase;
SRecord: TDxSearchRecord;
procedure OnSearch;
var
i: Integer;
begin
Url : = Url + ' &start= ' + inttostr(FSearchStart);
HttpReq.open( ' Get ' , Url, False, EmptyParam, EmptyParam);
HttpReq.send(EmptyParam); // 开始搜索
Url : = HttpReq.responseText;
Json : = Tlkjson.ParseText(url) as TlkJSONobject;
ChildJson : = Json.Field[ ' responseData ' ];
if ChildJson.SelfType = jsObject then
begin
ChildJson : = ChildJson.Field[ ' results ' ];
if ChildJson.SelfType = jsList then
begin
for i : = 0 to ChildJson.Count - 1 do
begin
tmpJson : = ChildJson.Child[i];
SRecord : = TDxSearchRecord.Create;
SRecord.FromJsonObj(tmpJson as TlkJSONobject);
FRecords.List.Add(SRecord);
end ;
end ;
if ClearOld or (Length(Pages) = 0 ) then
begin
// 查看分页情况,获得分页情况
ChildJson : = Json.Field[ ' responseData ' ].Field[ ' cursor ' ].Field[ ' pages ' ];
if ChildJson.SelfType = jsList then
begin
SetLength(Pages,ChildJson.Count);
for i : = 0 to ChildJson.Count - 1 do
begin
tmpJson : = ChildJson.Child[i];
Pages[i] : = StrToInt(VarToStr(tmpJson.Field[ ' start ' ].Value));
end ;
end ;
ChildJson : = Json.Field[ ' responseData ' ].Field[ ' cursor ' ];
FCurPageIndex : = strtoint(vartostr(ChildJson.Field[ ' currentPageIndex ' ].Value));
end
else
begin
ChildJson : = Json.Field[ ' responseData ' ].Field[ ' cursor ' ];
FCurPageIndex : = strtoint(vartostr(ChildJson.Field[ ' currentPageIndex ' ].Value));
end ;
end ;
Json.Free;
end ;
begin
FCurSearchInfo : = SearchInfo;
case FSearchType of
Sh_Web: Url : = BaseUrl + ' web?v= ' + FVersion + ' &q= ' ;
Sh_Local: Url : = BaseUrl + ' local?v= ' + FVersion + ' &q= ' ;
Sh_Video: Url : = BaseUrl + ' video?v= ' + FVersion + ' &q= ' ;
Sh_Blog: Url : = BaseUrl + ' blogs?v= ' + FVersion + ' &q= ' ;
Sh_News: Url : = BaseUrl + ' news?v= ' + FVersion + ' &q= ' ;
Sh_Book: Url : = BaseUrl + ' books?v= ' + FVersion + ' &q= ' ;
Sh_Image: Url : = BaseUrl + ' images?v= ' + FVersion + ' &q= ' ;
Sh_patent: Url : = BaseUrl + ' patent?v= ' + FVersion + ' &q= ' ;
else Url : = '' ;
end ;
if Url <> '' then
begin
FRecords.FSearchType : = FSearchType;
if ClearOld then
FRecords.Clear;
Url : = Url + ToUTF8Encode(SearchInfo);
if FBigSearchSize then
Url : = Url + ' &rsz=large '
else Url : = Url + ' &rsz=small ' ;
if FSearchStart < 0 then
begin
// 搜索返回所有结果
ClearOld : = False;
FSearchStart : = 0 ;
OnSearch;
while NextSearch do ; // 搜索下一个
end
else
begin
OnSearch;
end ;
end ;
end ;

{ TDxSearchRecord }

constructor TDxSearchRecord.Create;
begin
RetList : = TStringList.Create;
end ;

destructor TDxSearchRecord.Destroy;
begin
RetList.Free;
inherited ;
end ;

function TDxSearchRecord.FieldByName(FieldName: string ): string ;
var
index: Integer;
begin
index : = RetList.IndexOfName(FieldName);
if (index > - 1 ) and (index < FieldCount) then
Result : = RetList.ValueFromIndex[index]
else Result : = '' ;
end ;

procedure TDxSearchRecord.FromJsonObj(JsonObj: TlkJsonObject);
var
i: Integer;
str: String;
begin
RetList.Clear;
for i : = 0 to JsonObj.Count - 1 do
begin
str : = JsonObj.NameOf[i];
str : = str + ' = ' + VarToStr(JsonObj.FieldByIndex[i].Value);
RetList.Add(str);
end ;
end ;

function TDxSearchRecord.GetFieldCount: Integer;
begin
Result : = RetList.Count;
end ;

function TDxSearchRecord.GetFields(index: Integer): string ;
begin
if (index > - 1 ) and (index < FieldCount) then
Result : = RetList.Names[index]
else Result : = '' ;
end ;

function TDxSearchRecord.GetValues(index: Integer): string ;
begin
if (index > - 1 ) and (index < FieldCount) then
Result : = RetList.ValueFromIndex[index]
else Result : = '' ;
end ;

{ TDxSearchRecords }

procedure TDxSearchRecords.Clear;
begin
while List.Count > 0 do
begin
TDxSearchRecord(List[List.Count - 1 ]).Free;
List.Delete(List.Count - 1 );
end ;
end ;

constructor TDxSearchRecords.Create;
begin
List : = TList.Create;
FSearchType : = Sh_Web;
end ;

destructor TDxSearchRecords.Destroy;
begin
clear;
List.Free;
inherited ;
end ;

function TDxSearchRecords.GetCount: Integer;
begin
Result : = List.Count;
end ;

function TDxSearchRecords.GetRecords(index: Integer): TDxSearchRecord;
begin
if (index > - 1 ) and (index < Count) then
Result : = List[index]
else Result : = nil ;
end ;

end .