1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
|
unit sqldbrestdataset;
{$mode objfpc}{$H+}
interface
uses
Classes, SysUtils, db, fpjson, fpjsondataset;
Type
{ TSQLDBRestDataset }
TSQLDBRestDataset = Class(TBaseJSONDataset)
private
Protected
function GetStringFieldLength(F: TJSONObject; AName: String; AIndex: Integer): integer;virtual;
function StringToFieldType(S: String): TFieldType; virtual;
Function CreateFieldMapper: TJSONFieldMapper; override;
Procedure MetaDataToFieldDefs; override;
Public
procedure LoadFromStream(S: TStream);
end;
implementation
type
PRecInfo = ^TRecInfo;
TRecInfo = record
Index: Integer;
Bookmark: Longint;
BookmarkFlag: TBookmarkFlag;
end;
procedure TSQLDBRestDataset.LoadFromStream(S: TStream);
Var
D : TJSONData;
O : TJSONObject absolute D;
N : String;
I : Integer;
begin
D:=GetJSON(S);
try
if (D.JSONType<>jtObject) then
Raise EJSONDataset.Create('Not a valid JSON data packet');
N:='data';
// Check metadata
I:=O.IndexOfName('metaData');
if (I<>-1) then
begin
If (O.Items[i].JSONType<>jtObject) then
Raise EJSONDataset.Create('Invalid JSON metaData in data packet.');
Metadata:=O.Objects['metaData'];
O.Extract(I);
end;
// Check rows
I:=O.IndexOfName(N);
if (I=-1) then
Raise EJSONDataset.Create('Missing data in data packet');
if (O.Items[i].JSONType<>jtArray) then
Raise EJSONDataset.Create('Rows element must be an array');
Rows:=O.Items[i] as TJSONArray;
O.Extract(I);
OwnsData:=True;
finally
D.Free;
end;
end;
function TSQLDBRestDataset.StringToFieldType(S: String): TFieldType;
begin
if (s='int') then
Result:=ftInteger
else if (s='bigint') then
Result:=ftLargeInt
else if (s='float') then
Result:=ftFloat
else if (s='bool') then
Result:=ftString // Buggy TJSONDataset in 3.0.4
else if (s='date') then
Result:=ftDate
else if (s='datetime') then
Result:=ftDateTime
else if (s='time') then
Result:=ftTime
else if (s='blob') then
Result:=ftBlob
else if (s='string') then
Result:=ftString
else
if MapUnknownToStringType then
Result:=ftString
else
Raise EJSONDataset.CreateFmt('Unknown JSON data type : %s',[s]);
end;
function TSQLDBRestDataset.CreateFieldMapper: TJSONFieldMapper;
begin
Result:=TJSONObjectFieldMapper.Create;
end;
function TSQLDBRestDataset.GetStringFieldLength(F: TJSONObject; AName: String;
AIndex: Integer): integer;
Var
I,L : Integer;
D : TJSONData;
begin
Result:=F.Get('maxLen',0);
if (Result=0) then
Result:=255;
end;
procedure TSQLDBRestDataset.MetaDataToFieldDefs;
Var
A : TJSONArray;
F : TJSONObject;
I,FS : Integer;
N,D: String;
ft: TFieldType;
begin
FieldDefs.Clear;
A:=Metadata.Get('fields',TJSONArray(Nil));
if A=Nil then
Raise EJSONDataset.Create('Invalid metadata object');
For I:=0 to A.Count-1 do
begin
F:=A.Objects[i];
N:=F.Get('name','');
If N='' then
Raise EJSONDataset.CreateFmt('Field definition %d in has no or invalid name property',[i]);
D:=F.Get('type','');
If (D='') then
ft:=ftstring
else
ft:=StringToFieldType(String(D));
if (ft=ftString) then
fs:=GetStringFieldLength(F,N,I)
else
fs:=0;
FieldDefs.Add(N,ft,fs);
end;
end;
end.
|
