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
|
#pragma once
#include <algorithm>
#include <cctype>
#include <iomanip>
#include <ostream>
#include <ranges>
#include <span>
#include <string>
#include <string_view>
#include <vector>
// IWYU pragma: no_include <ctype.h>
namespace http_helpers
{
enum class ContentType
{
NoMatch,
ANY, // Accepts: */*
CBOR,
HTML,
JSON,
OctetStream,
EventStream,
};
struct ContentTypePair
{
std::string_view contentTypeString;
ContentType contentTypeEnum;
};
constexpr std::array<ContentTypePair, 5> contentTypes{{
{"application/cbor", ContentType::CBOR},
{"application/json", ContentType::JSON},
{"application/octet-stream", ContentType::OctetStream},
{"text/html", ContentType::HTML},
{"text/event-stream", ContentType::EventStream},
}};
inline ContentType
getPreferredContentType(std::string_view header,
std::span<const ContentType> preferedOrder)
{
size_t lastIndex = 0;
while (lastIndex < header.size() + 1)
{
size_t index = header.find(',', lastIndex);
if (index == std::string_view::npos)
{
index = header.size();
}
std::string_view encoding = header.substr(lastIndex, index);
if (!header.empty())
{
header.remove_prefix(1);
}
lastIndex = index + 1;
// ignore any q-factor weighting (;q=)
std::size_t separator = encoding.find(";q=");
if (separator != std::string_view::npos)
{
encoding = encoding.substr(0, separator);
}
// If the client allows any encoding, given them the first one on the
// servers list
if (encoding == "*/*")
{
return ContentType::ANY;
}
const auto* knownContentType = std::ranges::find_if(
contentTypes, [encoding](const ContentTypePair& pair) {
return pair.contentTypeString == encoding;
});
if (knownContentType == contentTypes.end())
{
// not able to find content type in list
continue;
}
// Not one of the types requested
if (std::ranges::find(preferedOrder,
knownContentType->contentTypeEnum) ==
preferedOrder.end())
{
continue;
}
return knownContentType->contentTypeEnum;
}
return ContentType::NoMatch;
}
inline bool isContentTypeAllowed(std::string_view header, ContentType type,
bool allowWildcard)
{
auto types = std::to_array({type});
ContentType allowed = getPreferredContentType(header, types);
if (allowed == ContentType::ANY)
{
return allowWildcard;
}
return type == allowed;
}
} // namespace http_helpers
|
