HttpUtility::SendJsonBody(): auto-sanitize non-UTF-8 JSON

[Al2Klimov]

fixes #4703

[Al2Klimov]

Test protocol

1. Build Icinga 2
2. Setup API
3. Start the daemon
4. Create a host via API
5. Stop the daemon

Both the API response and the state file look fine.

[Al2Klimov]

In addition the API query results differ.

$ hexdump -C <lolcat.conf
00000000  6f 62 6a 65 63 74 20 48  6f 73 74 20 22 6c 6f 6c  |object Host "lol|
00000010  63 61 74 22 20 7b 0a 09  63 68 65 63 6b 5f 63 6f  |cat" {..check_co|
00000020  6d 6d 61 6e 64 20 3d 20  22 68 6f 73 74 61 6c 69  |mmand = "hostali|
00000030  76 65 22 0a 09 76 65 72  73 69 6f 6e 20 3d 20 31  |ve"..version = 1|
00000040  35 34 33 35 37 30 36 35  37 2e 33 32 30 33 30 36  |543570657.320306|
00000050  0a 09 7a 6f 6e 65 20 3d  20 22 43 45 4e 53 4f 52  |..zone = "CENSOR|
00000060  45 44 22 0a 09 76 61 72  73 2e 66 6f 6f 62 61 72  |ED"..vars.foobar|
00000070  20 3d 20 22 80 81 82 83  84 85 86 87 88 89 8a 8b  | = "............|
00000080  8c 8d 8e 8f 90 91 92 93  94 95 96 97 98 99 9a 9b  |................|
00000090  9c 9d 9e 9f a0 a1 a2 a3  a4 a5 a6 a7 a8 a9 aa ab  |................|
000000a0  ac ad ae af b0 b1 b2 b3  b4 b5 b6 b7 b8 b9 ba bb  |................|
000000b0  bc bd be bf c0 c1 c2 c3  c4 c5 c6 c7 c8 c9 ca cb  |................|
000000c0  cc cd ce cf d0 d1 d2 d3  d4 d5 d6 d7 d8 d9 da db  |................|
000000d0  dc dd de df e0 e1 e2 e3  e4 e5 e6 e7 e8 e9 ea eb  |................|
000000e0  ec ed ee ef f0 f1 f2 f3  f4 f5 f6 f7 f8 f9 fa fb  |................|
000000f0  fc fd fe ff 22 0a 7d 0a                           |....".}.|
000000f8

$ base64 -b 72 <lolcat.conf
b2JqZWN0IEhvc3QgImxvbGNhdCIgewoJY2hlY2tfY29tbWFuZCA9ICJob3N0YWxpdmUiCgl2
ZXJzaW9uID0gMTU0MzU3MDY1Ny4zMjAzMDYKCXpvbmUgPSAiQ0VOU09SRUQiCgl2YXJzLmZv
b2JhciA9ICKAgYKDhIWGh4iJiouMjY6PkJGSk5SVlpeYmZqbnJ2en6ChoqOkpaanqKmqq6yt
rq+wsbKztLW2t7i5uru8vb6/wMHCw8TFxsfIycrLzM3Oz9DR0tPU1dbX2Nna29zd3t/g4eLj
5OXm5+jp6uvs7e7v8PHy8/T19vf4+fr7/P3+/yIKfQo=

$ curl -k -H 'Accept: application/json' "$(./url-cluster.sh)/v1/objects/hosts/lolcat" |hexdump -C # v2.10.2
(...)
00000900  2c 22 76 61 72 73 22 3a  7b 22 66 6f 6f 62 61 72  |,"vars":{"foobar|
00000910  22 3a 22 80 81 82 83 84  85 86 87 88 89 8a 8b 8c  |":".............|
00000920  8d 8e 8f 90 91 92 93 94  95 96 97 98 99 9a 9b 9c  |................|
00000930  9d 9e 9f a0 a1 a2 a3 a4  a5 a6 a7 a8 a9 aa ab ac  |................|
00000940  ad ae af b0 b1 b2 b3 b4  b5 b6 b7 b8 b9 ba bb bc  |................|
00000950  bd be bf c0 c1 c2 c3 c4  c5 c6 c7 c8 c9 ca cb cc  |................|
00000960  cd ce cf d0 d1 d2 d3 d4  d5 d6 d7 d8 d9 da db dc  |................|
00000970  dd de df e0 e1 e2 e3 e4  e5 e6 e7 e8 e9 ea eb ec  |................|
00000980  ed ee ef f0 f1 f2 f3 f4  f5 f6 f7 f8 f9 fa fb fc  |................|
00000990  fd fe ff 22 7d 2c 22 76  65 72 73 69 6f 6e 22 3a  |..."},"version":|
(...)

$ curl -k -H 'Accept: application/json' "$(./url-cluster.sh)/v1/objects/hosts/lolcat" |hexdump -C # this PR
(...)
00000900  2c 22 76 61 72 73 22 3a  7b 22 66 6f 6f 62 61 72  |,"vars":{"foobar|
00000910  22 3a 22 ef bf bd ef bf  bd ef bf bd ef bf bd ef  |":".............|
00000920  bf bd ef bf bd ef bf bd  ef bf bd ef bf bd ef bf  |................|
00000930  bd ef bf bd ef bf bd ef  bf bd ef bf bd ef bf bd  |................|
00000940  ef bf bd ef bf bd ef bf  bd ef bf bd ef bf bd ef  |................|
00000950  bf bd ef bf bd ef bf bd  ef bf bd ef bf bd ef bf  |................|
00000960  bd ef bf bd ef bf bd ef  bf bd ef bf bd ef bf bd  |................|
00000970  ef bf bd ef bf bd ef bf  bd ef bf bd ef bf bd ef  |................|
00000980  bf bd ef bf bd ef bf bd  ef bf bd ef bf bd ef bf  |................|
00000990  bd ef bf bd ef bf bd ef  bf bd ef bf bd ef bf bd  |................|
000009a0  ef bf bd ef bf bd ef bf  bd ef bf bd ef bf bd ef  |................|
000009b0  bf bd ef bf bd ef bf bd  ef bf bd ef bf bd ef bf  |................|
000009c0  bd ef bf bd ef bf bd ef  bf bd ef bf bd ef bf bd  |................|
000009d0  ef bf bd ef bf bd ef bf  bd ef bf bd ef bf bd ef  |................|
000009e0  bf bd ef bf bd ef bf bd  ef bf bd ef bf bd ef bf  |................|
000009f0  bd ef bf bd ef bf bd ef  bf bd ef bf bd ef bf bd  |................|
00000a00  ef bf bd ef bf bd ef bf  bd ef bf bd ef bf bd ef  |................|
00000a10  bf bd ef bf bd ef bf bd  ef bf bd ef bf bd ef bf  |................|
00000a20  bd ef bf bd ef bf bd ef  bf bd ef bf bd ef bf bd  |................|
00000a30  ef bf bd ef bf bd ef bf  bd ef bf bd ef bf bd ef  |................|
00000a40  bf bd ef bf bd ef bf bd  ef bf bd ef bf bd ef bf  |................|
00000a50  bd ef bf bd ef bf bd ef  bf bd ef bf bd ef bf bd  |................|
00000a60  ef bf bd ef bf bd ef bf  bd ef bf bd ef bf bd ef  |................|
00000a70  bf bd ef bf bd ef bf bd  ef bf bd ef bf bd ef bf  |................|
00000a80  bd ef bf bd ef bf bd ef  bf bd ef bf bd ef bf bd  |................|
00000a90  ef bf bd 22 7d 2c 22 76  65 72 73 69 6f 6e 22 3a  |..."},"version":|
(...)

[dnsmichi]

I will be working on #6684 soon and replace the entire JSON library causing memory leaks. When at it, I'll test this PR too.