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nnsee
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Content-Type header parser (#259)
Co-authored-by: ringabout <[email protected]>
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‎src/prologue/core/contenttype.nim

+118
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,118 @@
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import std/[strutils, tables, strformat, sequtils]
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type
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MediaType* = object
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mainType*: string
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subType*: string
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parameters*: Table[string, string]
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const
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# Token characters as per RFC 7230 section 3.2.6
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# https://datatracker.ietf.org/doc/html/rfc7230#section-3.2.6
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VALID_TOKEN_CHARACTERS = {'a'..'z', 'A'..'Z', '0'..'9',
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'!', '#', '$', '%', '&', '\'', '*', '+', '-', '.', '^', '_', '`', '|', '~'}
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proc skipWhitespace(headerValue: string, i: var int) =
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## Skips the next whitespace characters beginning from index ``i``.
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## This updates the param ``i``
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while i < headerValue.len and headerValue[i] in Whitespace:
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inc i
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proc parseContentType*(headerValue: string): MediaType =
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## Parses a Content-Type header according to RFC 7230, RFC 2045, and RFC 2046.
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## Returns a MediaType object containing the main type, sub type, and parameters.
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runnableExamples:
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let mediaType = parseContentType("text/plain; charset=\"utf-8\"")
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doAssert mediaType.mainType == "text"
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doAssert mediaType.subType == "plain"
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doAssert mediaType.parameters.len == 1
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doAssert mediaType.parameters["charset"] == "utf-8"
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result = MediaType(parameters: initTable[string, string]())
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var
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i = 0
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headerLen = headerValue.len
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headerValue.skipWhitespace(i)
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# media type
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let mediaTypeStart = i
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while i < headerLen and headerValue[i] notin {';', ' ', '\t'}:
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inc i
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let mediaType = headerValue[mediaTypeStart..<i].strip()
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let typeParts = mediaType.split('/')
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if typeParts.len != 2:
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raise newException(ValueError, &"Invalid media type: {mediaType}")
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result.mainType = typeParts[0].toLowerAscii
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result.subType = typeParts[1].toLowerAscii
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headerValue.skipWhitespace(i)
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# params
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while i < headerLen and headerValue[i] == ';':
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inc i
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headerValue.skipWhitespace(i)
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# param name
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let paramNameStart = i
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while i < headerLen and headerValue[i] notin {'=', ';', ' ', '\t'}:
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inc i
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if i >= headerLen or headerValue[i] != '=':
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# this is a malformed parameter - skip it
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while i < headerLen and headerValue[i] != ';':
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inc i
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continue
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let paramName = headerValue[paramNameStart..<i].strip().toLowerAscii()
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inc i
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headerValue.skipWhitespace(i)
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# param value
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var
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paramValue: string
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foundClosingQuote = false
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if i < headerLen and headerValue[i] == '"':
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# quoted value
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inc i
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let valueStart = i
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while i < headerLen:
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if headerValue[i] == '\\' and i + 1 < headerLen and headerValue[i + 1] == '"':
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inc i, 2
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elif headerValue[i] == '"':
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paramValue = headerValue[valueStart..<i]
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inc i
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foundClosingQuote = true
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break
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else:
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inc i
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if not foundClosingQuote:
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paramValue = headerValue[valueStart..<headerLen]
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else:
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# unquoted value
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let valueStart = i
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while i < headerLen and headerValue[i] notin {';', ' ', '\t'}:
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inc i
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paramValue = headerValue[valueStart..<i]
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result.parameters[paramName] = paramValue
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headerValue.skipWhitespace(i)
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proc `$`*(mediaType: MediaType): string =
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## Convert MediaType to string representation
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result = mediaType.mainType & "/" & mediaType.subType
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for name, value in mediaType.parameters:
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if value.anyIt(it notin VALID_TOKEN_CHARACTERS):
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result.add(&"; {name}=\"{value}\"")
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else:
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result.add(&"; {name}={value}")

‎src/prologue/core/form.nim

+13-5
Original file line numberDiff line numberDiff line change
@@ -12,23 +12,30 @@
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# See the License for the specific language governing permissions and
1313
# limitations under the License.
1414

15-
1615
import std/[strtabs, strutils, strformat, parseutils, tables]
1716
from std/uri import decodeQuery
1817

1918
import ./httpcore/httplogue
2019
from ./types import FormPart, initFormPart, `[]=`
2120
import ./request
21+
import ./contenttype
2222

2323

2424
func parseFormPart*(body, contentType: string): FormPart =
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## Parses form part of the body of the request.
2626
let
27-
sep = contentType[contentType.rfind("boundary") + 9 .. ^1]
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mediaType = parseContentType(contentType)
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sep = if "boundary" in mediaType.parameters: mediaType.parameters["boundary"] else: ""
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startSep = fmt"--{sep}"
2930
endSep = fmt"--{sep}--"
3031
startPos = find(body, startSep)
3132
endPos = rfind(body, endSep)
33+
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# make sure we found valid boundaries
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if startPos < 0 or endPos < 0 or startPos >= endPos:
36+
return initFormPart()
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let
3239
formData = body[startPos ..< endPos]
3340
formDataSeq = formData.split(startSep & "\c\L")
3441

@@ -89,18 +96,19 @@ func parseFormPart*(body, contentType: string): FormPart =
8996

9097
func parseFormParams*(request: var Request, contentType: string) =
9198
## Parses get or post or query parameters.
92-
if "form-urlencoded" in contentType:
99+
let mediaType = parseContentType(contentType)
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101+
if mediaType.mainType == "application" and mediaType.subType == "x-www-form-urlencoded":
93102
request.formParams = initFormPart()
94103
if request.reqMethod == HttpPost:
95104
for (key, value) in decodeQuery(request.body):
96105
# formPrams and postParams for secret event
97106
request.formParams[key] = value
98107
request.postParams[key] = value
99-
elif "multipart/form-data" in contentType and "boundary" in contentType:
108+
elif mediaType.mainType == "multipart" and mediaType.subType == "form-data" and "boundary" in mediaType.parameters:
100109
request.formParams = parseFormPart(request.body, contentType)
101110

102111
# /student?name=simon&age=sixteen
103112
# query -> name=simon&age=sixteen
104-
105113
for (key, value) in decodeQuery(request.query):
106114
request.queryParams[key] = value

‎tests/unit/tunit_core/tunit_contenttype.nim

+164
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import ../../../src/prologue/core/contenttype
2+
import std/[tables, strutils, strformat]
3+
4+
block:
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let mediaType = parseContentType("text/plain")
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doAssert mediaType.mainType == "text"
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doAssert mediaType.subType == "plain"
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doAssert mediaType.parameters.len == 0
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block:
11+
let mediaType = parseContentType("text/plain; charset=utf-8")
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doAssert mediaType.mainType == "text"
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doAssert mediaType.subType == "plain"
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doAssert mediaType.parameters.len == 1
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doAssert "charset" in mediaType.parameters
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doAssert mediaType.parameters["charset"] == "utf-8"
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18+
block:
19+
let mediaType = parseContentType("text/plain; charset=utf-8; format=flowed")
20+
doAssert mediaType.mainType == "text"
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doAssert mediaType.subType == "plain"
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doAssert mediaType.parameters.len == 2
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doAssert "charset" in mediaType.parameters
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doAssert "format" in mediaType.parameters
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doAssert mediaType.parameters["charset"] == "utf-8"
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doAssert mediaType.parameters["format"] == "flowed"
27+
28+
block:
29+
let mediaType = parseContentType("text/plain; charset=\"utf-8\"")
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doAssert mediaType.mainType == "text"
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doAssert mediaType.subType == "plain"
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doAssert mediaType.parameters.len == 1
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doAssert "charset" in mediaType.parameters
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doAssert mediaType.parameters["charset"] == "utf-8"
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36+
block:
37+
let mediaType = parseContentType("application/json; charset=\"utf 8\"")
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doAssert mediaType.mainType == "application"
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doAssert mediaType.subType == "json"
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doAssert mediaType.parameters.len == 1
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doAssert "charset" in mediaType.parameters
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doAssert mediaType.parameters["charset"] == "utf 8"
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44+
block:
45+
let mediaType = parseContentType("multipart/form-data; boundary=---------------------------263701891623491983764541468")
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doAssert mediaType.mainType == "multipart"
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doAssert mediaType.subType == "form-data"
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doAssert mediaType.parameters.len == 1
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doAssert "boundary" in mediaType.parameters
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doAssert mediaType.parameters["boundary"] == "---------------------------263701891623491983764541468"
51+
52+
block:
53+
let mediaType = parseContentType("multipart/form-data; boundary=\"simple-boundary\"")
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doAssert mediaType.mainType == "multipart"
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doAssert mediaType.subType == "form-data"
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doAssert mediaType.parameters.len == 1
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doAssert "boundary" in mediaType.parameters
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doAssert mediaType.parameters["boundary"] == "simple-boundary"
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60+
block:
61+
let mediaType = parseContentType("multipart/form-data; boundary=\"boundary with spaces and-dashes\"")
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doAssert mediaType.mainType == "multipart"
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doAssert mediaType.subType == "form-data"
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doAssert mediaType.parameters.len == 1
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doAssert "boundary" in mediaType.parameters
66+
doAssert mediaType.parameters["boundary"] == "boundary with spaces and-dashes"
67+
68+
block:
69+
let mediaType = parseContentType("text/plain; description=\"This is a \\\"quoted\\\" description\"")
70+
doAssert mediaType.mainType == "text"
71+
doAssert mediaType.subType == "plain"
72+
doAssert mediaType.parameters.len == 1
73+
doAssert "description" in mediaType.parameters
74+
doAssert mediaType.parameters["description"] == "This is a \\\"quoted\\\" description"
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76+
block:
77+
let mediaType = parseContentType("TeXt/PlAiN; ChArSeT=UTF-8")
78+
doAssert mediaType.mainType == "text"
79+
doAssert mediaType.subType == "plain"
80+
doAssert mediaType.parameters.len == 1
81+
doAssert "charset" in mediaType.parameters
82+
doAssert mediaType.parameters["charset"] == "UTF-8"
83+
84+
block:
85+
let mediaType = parseContentType(" text/plain ; charset=utf-8 ; format=flowed ")
86+
doAssert mediaType.mainType == "text"
87+
doAssert mediaType.subType == "plain"
88+
doAssert mediaType.parameters.len == 2
89+
doAssert "charset" in mediaType.parameters
90+
doAssert "format" in mediaType.parameters
91+
doAssert mediaType.parameters["charset"] == "utf-8"
92+
doAssert mediaType.parameters["format"] == "flowed"
93+
94+
block:
95+
let mediaType = parseContentType("text/plain; charset")
96+
doAssert mediaType.mainType == "text"
97+
doAssert mediaType.subType == "plain"
98+
doAssert mediaType.parameters.len == 0
99+
100+
block:
101+
try:
102+
discard parseContentType("text")
103+
doAssert false, "Should have raised an exception"
104+
except ValueError:
105+
doAssert true
106+
107+
block:
108+
let mediaType = parseContentType("text/plain; charset=utf-8; format=flowed")
109+
let str = $mediaType
110+
doAssert str.startsWith("text/plain")
111+
doAssert "; charset=utf-8" in str
112+
doAssert "; format=flowed" in str
113+
114+
block:
115+
var mediaType = MediaType(
116+
mainType: "multipart",
117+
subType: "form-data",
118+
parameters: {"boundary": "simple boundary with spaces"}.toTable
119+
)
120+
let str = $mediaType
121+
doAssert str == "multipart/form-data; boundary=\"simple boundary with spaces\""
122+
123+
block:
124+
var mediaType = MediaType(
125+
mainType: "text",
126+
subType: "plain",
127+
parameters: {
128+
"charset": "utf-8",
129+
"description": "This is a description with spaces"
130+
}.toTable
131+
)
132+
let str = $mediaType
133+
doAssert str.startsWith("text/plain")
134+
doAssert "; charset=utf-8" in str
135+
doAssert "; description=\"This is a description with spaces\"" in str
136+
137+
# some real-world examples
138+
block:
139+
let examples = [
140+
"text/html; charset=UTF-8",
141+
"application/json",
142+
"application/x-www-form-urlencoded",
143+
"multipart/form-data; boundary=something",
144+
"image/jpeg",
145+
"application/octet-stream",
146+
"text/css; charset=utf-8",
147+
"application/javascript",
148+
"multipart/mixed; boundary=\"frontier\"",
149+
"application/pdf",
150+
"text/plain; charset=us-ascii"
151+
]
152+
153+
for example in examples:
154+
let mediaType = parseContentType(example)
155+
let roundTrip = $mediaType
156+
157+
let roundTripMediaType = parseContentType(roundTrip)
158+
doAssert roundTripMediaType.mainType == mediaType.mainType
159+
doAssert roundTripMediaType.subType == mediaType.subType
160+
doAssert roundTripMediaType.parameters.len == mediaType.parameters.len
161+
162+
for key, value in mediaType.parameters:
163+
doAssert key in roundTripMediaType.parameters
164+
doAssert roundTripMediaType.parameters[key] == value

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